solving systems by substitution

how would you you find the answer for
-5x + y = -2
-3x+6y=-12 ? having some issues with how to this​

Answers

Answer 1

9514 1404 393

Answer:

  (x, y) = (0, -2)

Step-by-step explanation:

When solving by substitution, you usually want to find an expression for one of the variables in terms of the other. So, the first thing you look for is an equation that has a coefficient of 1 or -1 on one of the variables. Recognizing that the second equation's terms all have a common factor of 3, you basically have two choices.

Substitute for y

Using equation 1, you can write an expression for y:

  y = 5x -2 . . . . . . add 5x to both sides

Then substituting this into the original equation 2, you have ...

  -3x +6(5x -2) = -12

  27x -12 = -12 . . . . . . . simplify

  27x = 0 . . . . . . . . . add 12

  x = 0 . . . . . . . . .  divide by 27

  y = 5(0) -2 = -2 . . . . find y using the expression for substitution

The solution is (x, y) = (0, -2).

__

Substitute for x

If you decide you'd rather substitute for x, you can solve the second equation easily for x.

  -3x +6y = -12

  x -2y = 4 . . . . . . divide by -3

  x = 2y +4 . . . . . . add 2y

Substituting for x in the first equation gives ...

  -5(2y +4) +y = -2 . . . . substitute for x

  -9y -20 = -2 . . . . . . . simplify

  -9y = 18 . . . . . . . . .  add 20

  y = -2 . . . . . . . . . . . divide by -9

  x = 2(-2) +4 = 0 . . . . find x using the expression for substitution

The solution is (x, y) = (0, -2).

_____

Additional comment

In some cases, there are no variables that have a coefficient of ±1, so you just need to "bite the bullet" and deal with the resulting fractions.

Example:

  solve for y: -5x +2y = -2

     2y = 5x -2

     y = 5/2x -1 . . . . expression used to substitute for y

Of course, you can multiply the equation after substitution by 2 to eliminate fractions, or just work the problem as is. The point of looking for coefficients of ±1 is to avoid having to do arithmetic with fractions. It can help avoid errors to work with integers, but ultimately the method is the same regardless of the form of the numbers.

__

You don't always have to substitute for the "bare" variable. Sometimes it can save steps to substitute for expressions instead of variables. If our system of equations were ...

-5x +2y = -2-3x +6y = -12

You can substitute into the second equation for (2y). In that case, the second equation becomes ...

  -3x +3(2y) = -12

  -3x +3(5x-2) = -12 . . . . . . where 2y = 5x -2


Related Questions

Put the following equation of a line into slope-intercept form, simplifying all
fractions.
18x + 3y = -18

Answers

At the moment it’s in standard form. We can easily turn this into slope int form (y= mx + b) tho

3y= -18x -18
y= -6x - 6

Can someone check my answers if they are correct or incorrect? If it is incorrect, please let me know why it is incorrect please.

Answers

This answer is incorrect, try again

Sandra ride her bike 5 times as many miles as Barbara. If b, the distance Barbara rode equals 3.4 miles what is the correct expression and the distance Sandra rode

Answers

Answer:

b + 5; when b = 3.4 the distance Sandra rode is 17 miles.

Step-by-step explanation:

List the sides of the triangle in order from largest to smallest.

Answers

translate it to english

1. Ten times the sum of -270 and a number gives -20.​

Answers

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Answer:

equation: 10(-270 +n) = -20number: 268

Step-by-step explanation:

If n represents the number, we have ...

  10(-270 +n) = -20 . . . an equation for n

__

The solution can be found as ...

  -270 +n = -2 . . . . . divide by 10

  n = 268 . . . . . . . add 270

The number is 268.

210
To rationalize the denominator of
3.11,You should multiply the expression by which fraction?
11
2- V10
2- 10
3- V11
3- V11

Answers

The answer is The second one because I took this test before and I got it right

We should multiply the expression by √11/ √11 fraction.

What is the fundamental principle of multiplication?

Multiplication is the mathematical operation that is used to determine the product of two or more numbers.

To rationalize this, we multiply both the denominator and denominator by the conjugate of the denominator.

The denominator is 2-√10 and its conjugate is; (2+√10).

(2√10)/(3√11) = (2√10)/(3√11)

                      =  ((2√10)√11/(3√11) √11

                =    (2√110)/33

This is the rationalized expression.  

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1. Given the line of best fit y = 6.2x + 13, what is the residual for the point (10,80)? (1 pt)
A. 75
B. 5
C. 499
D. 55

Answers

Answer:

c

Step-by-step explanation:

The residual for the point line (10,80) is option A 75. at the given line which best fits y = 6.2x + 13.

What is a straight line graph?

The graph follows a straight line equation shows a straight line graph.

equation of a straight line is   y=mx+cy represents vertical line y-axis.x represents the horizontal line x-axis.     m is the slope of the line

            slope(m)=tan∅=y axis/x axis.

c represents y-intercepts (it is the point at which the line cuts on the y-axis)

Straight line graphs show a linear relationship between the x and y values.

solving the equation:-

y = 6.2x + 13

putting value of X = 10

Y = 6.2 * 10 + 13

Y = 62 + 13

Y = 75

Hence the line best fit = 75.

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A study is conducted to examine the correlation between Training Time and the Error Rate of employees. If the correlation coefficient of Training Time and Error Rate is -0.76, what is your conclusion?
(The answer is NOT B) HELP Please!!
A Moderate positive correlation
B Strong negative correlation
C No conclusion possible
D No correlation is shown
E Strong positive correlation

Answers

Answer:

No conclusion possible

Question 1 The straight-line graph defined by the equation y = 2x – 4. will cut the y-axis at the point. ​

Answers

Answer:

(0;-4)

Step-by-step explanation:

cuz it cut the y-axis so x have to be 0

y=2*0 -4= -4

so the point is (0;-4)

A couple decide to have 5 children what if the probability that they will have at least one girl

Answers

The chance that they will have one girl is 1:5 because they are having 5 children and one is going to be a girl

Answer:

31/32

Step-by-step explanation:

There are 2^5, or 32 combinations.

There is only 1 combination which is all 5 children are boys.

So the probability that will have at least 1 girl is: 1 - 1/32 = 31/32

If only the height of a pyramid is doubled its volume is Also doubled true or false

Answers

Answer: true

Step-by-step explanation:

On their farm, Adam’s family maintains a storage that can hold 19.9 cubic yards (yd3) of grain. Use the fact that 1 yard is approximately equal to 0.9144 m to convert this volume to m3​

Answers

19.9 cubic yards converted to cubic meters is 15.21 m³.

How do you convert to cubic meters?

The volume of the storage is the amount of space inside it. Large volumes are measured in cubic metres.

Given this unit of conversion: 1 yard =  0.9144 m

To convert to cubic meters, find the cube: 0.9144³ = 0.764555

Now, multiply 0.764555 by 19.9 : 0.764555 x 19.9 = 15.21 m³

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Adam sleeps for nine hours each night, five nights a week, and 11 hours for two nights a week.
Which is closest to the percentage of the whole week that Adam spends sleeping?
A) 25%
B) 30%
C) 33%
D) 40%
E) 50%

Answers

Answer:

E

Step-by-step explanation:

The percentage of the whole week that Adam spends in sleeping is 33%.

What is percentage?

A percentage is a portion of a whole expressed as a number between 0 and 100 rather than as a fraction.

How to find percentage of a number?

A percentage is a number or ratio that can be expressed as a fraction of 100. If we have to calculate percent of a number, divide the number by the whole and multiply by 100.

According to the give question.

Adams sleeps for nine hours each night, five nights a week.

⇒ Number of hours he sleep for five nights = 5 × 9 = 45 hours

Also, 11 hours for two nights a week.

So, the total number of hours Adam sleeps in a week = 45 + 11 = 56 hours

And, total number of hours in a week = 24 × 7 = 168

Therefore,

The percentage of the whole week that Adam spends in sleeping

= (total number of hours Adam sleep in a week/Total numbers of hour in a week) × 100

[tex]=\frac{56}{168}[/tex] × 100

= 33.33%

= 33%

Hence, the percentage of the whole week that Adam spends in sleeping is 33%.

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If sin x = –0.1 and 270° < x < 360°, what is the value of x to the nearest degree?

Answers

Answer:

354°15'38.99''

Step-by-step explanation:

The equation of a line is (3)/(5)x+(1)/(3)y=(1)/(15) . The x-intercept of the line is , and its y-intercept is .

Answers

bxf-mgii-whr

Step-by-step explanation:

come I will teach

What is the range of this data: 42,20,36,51,60,28

Answers

Answer:

40

Step-by-step explanation:

range is the difference between the highest and lowest number.

60 is the highest and 20 is the lowest

60-20=40

Find the value of x.

Answers

Answer:

x=3

Step-by-step explanation:

Find the radius and use Pythagoras on the right side

A box contains two blue cards numbered 1 and 2, and three green numbered 1 through 3. A blue card ins picked, followed by a green card. Select sample space for such experiment
a) {1, 1), (1, 2, (1, 3)(2, 1), (2, 2), (2, 3)}
b) {(1, 1)(1, 2), (2, 1), (2, 2), (3, 1), (3, 2)}
c) {5}
d) {6}

Answers

Answer:

The answer is a.

consider a study conducted to determine the average protein intake among an adult population. Suppose that a confidence level of 85% is required with an interval about 10 units wide. if a preliminary data indicates a standard deviation of 20g, what sample of adults should be selected for the study?​

Answers

Answer:

made up of about 20 common amino acids. The proportion of these amino acids varies as a characteristic of a given protein, but all food proteins—with the exception of gelatin—contain some of each. Amino nitrogen accounts for approximately 16% of the weight of proteins. Amino acids are required for the synthesis of body protein and other important nitrogen-containing compounds, such as creatine, peptide hormones, and some neurotransmitters. Although allowances are expressed as protein, a the biological requirement is for amino acids.

Proteins and other nitrogenous compounds are being degraded and resynthesized continuously. Several times more protein is turned over daily within the body than is ordinarily consumed, indicating that reutilization of amino acids is a major feature of the economy of protein metabolism. This process of recapture is not completely efficient, and some amino acids are lost by oxidative catabolism. Metabolic products of amino acids (urea, creatinine, uric acid, and other nitrogenous products) are excreted in the urine; nitrogen is also lost in feces, sweat, and other body secretions and in sloughed skin, hair, and nails. A continuous supply of dietary amino acids is required to replace these losses, even after growth has ceased.

Amino acids consumed in excess of the amounts needed for the synthesis of nitrogenous tissue constituents are not stored but are degraded; the nitrogen is excreted as urea, and the keto acids left after removal of the amino groups are either utilized directly as sources of energy or are converted to carbohydrate or fat.

A car rental firm has 440 cars. Sixty-three of these cars have defective turn signals and 39 have defective tires. (Enter your probabilities as fractions.) (a) What is the probability that one of these cars selected at random does not have defective turn signals

Answers

Answer:

The probability is 0.857

Step-by-step explanation:

We know that:

There is a total of 440 cars

There are 63 cars with defective turn signals

There are 39 with defective tires.

Now we want to find the probability that a randomly selected car does not have defective turn signals.

If all the cars have the same probability of being selected, this probability will be equal to the quotient between the number of cars that do not have defective turn signals and the total number of cars.

We know that the total number of cars is 440

And 63 of these have defective turn signals, then the rest don't.

440 - 63 = 377 cars do not have defective turn signals.

Then the probability is:

P = 377/440 = 0.857

write your answer in simplest radical form​

Answers

Answer:

[tex]8\sqrt{2}[/tex]

Step-by-step explanation:

Maybe this image can help you.

Solve for x
-1/2x + 3 = -x + 7

Answers

Answer:

8

Step-by-step explanation:

If you add x to the left side of the equation you get positive 1/2x +3=7

you then would subtract 3 from 7 to get 4

this would leave you with 1/2x=4

if you divide 4 by 1/2 you get 8 as the answer.

Find the missing side lengths​

Answers

Answer:

y=9 and x=9*sqrt(2)

Step-by-step explanation:

tan(45)=9/y, 1=9/y, y=9

sin(45)=9/x, 1/sqrt(2)=9/x, x=9*sqrt(2)

Question
If a triangle has sides of length x x + 2, and x - 4, what is the perimeter of the triangle in terms of x?
О 3х - 6
03x - 2
3x + 2
O 3x + 6

Answers

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Answer:

  (b)  3x -2

Step-by-step explanation:

The perimeter is the sum of the side lengths:

  P = (x) +(x +2) +(x -4)

  P = (x +x +x) +(+2 -4)

  P = 3x -2


I need help answering this ASAP

Answers

Answer:

False, this is not a function

Step-by-step explanation:

This would not represent a function

This would fail the vertical line test

One value of the input has more than one value for the output

A stone is dropped into a lake, creating a circular ripple that travels outward at a speed of 60 cm/s. Find the rate at which the area within the circle is increasing after each of the following.
after 2s : cm2/s
after 5s : cm2/s
after 6s : cm2/s

Answers

9514 1404 393

Answer:

2s: 45,239 cm²/s5s: 113,097 cm²/s6s: 135,717 cm²/s

Step-by-step explanation:

The radius is a function of time:

  r(t) = 60t . . . . . radius in cm; time in s

Then the area of the circle is ...

  A = πr² = π(60t)² = 3600πt²

The rate of change of area is the derivative of this:

  A' = 2·3600πt = 7200πt

The rates of change of interest are ...

  after 2s: 45,239 cm²/s

  after 5s: 113,097 cm²/s

  after 6s: 135,717 cm²/s

Assume a significance level of α=0.05 and use the given information to complete parts​ (a) and​ (b) below. Original​ claim: More than 49​% of adults would erase all of their personal information online if they could. The hypothesis test results in a​ P-value of 0.0281.

Required:
a. State a conclusion about the null hypothesis.​
b. Without using technical​ terms, state a final conclusion that addresses the original claim. Which of the following is the correct​ conclusion?

1. The percentage of adults that would erase all of their personal information online if they could is more than or equal to 49​%.
2. There is sufficient evidence to support the claim that the percentage of adults that would erase all of their personal information online if they could is less than 49​%.
3. There is not sufficient evidence to support the claim that the percentage of adults that would erase all of their personal information online if they could is less than 49​%.
4. The percentage of adults that would erase all of their personal information online if they could is less than 49​%.

Answers

Answer:

Part a: The correct answer is A, reject H0 because p value is less than . Part B: The correct answer is C, the percentage of adults that would erase their personal information online if they could is more than 51%.

Step-by-step explanation:

part a. The essential idea of hypothesis testing in statistics is to evaluate the probability p (p value) of some representative parameter, compared to a level of likelihood that is set before starting the test (). In this case, we are interested in a level of likelihood , which means that if the probability of the parameter is less than 5%, we will reject the hypothesis that this parameter is representing, since it's so unlikely. Of course, the significance level is arbitrary and must be payed attention, according to the particular situation. Therefore, the correct anser is A.

part b. Since we rejected the hypothesis to a 5% significance level, we reject the fact that less than 51% of adults would erase their personal information online if they could. This is equivalent to saying that a percentage of adults equal to or more than 51% would erase their personal information if they

What is the distance between point C and point D?

Question 5 options:


A)


17 units


B)


13 units


C)


12 units


D)


√85 units

Answers

Answer:

B. 13 units

Step-by-step explanation:

let

(x1 , y1) = (-4 , -6)

(x2 , y2) = (1 , 6)

distance between CD = root (x2 - x1)^3 + (y2 - y1)

= root {1 - ( -4)}^2 + {6 - ( -6)}^2

= root {1 +4}^2 + {6+6}^2

= root 5^2 + 12^2

= root 25 + 144

= root 169

= 13 units ans

12 units is the answer for ur question

These two cones are similar. What is the value of x?

Answers

Answer:

A

Step-by-step explanation:

Given that the cones are similar then corresponding dimensions are in proportion, that is

[tex]\frac{12}{2}[/tex] = [tex]\frac{3}{x}[/tex] ( cross- multiply )

12x = 6 ( divide both sides by 12 )

x = 0.5 → A

Find the missing side round to the nearest tenth

Answers

Answer:  11.6

======================================================

Work Shown:

sin(angle) = opposite/hypotenuse

sin(29) = x/24

24*sin(29) = x

x = 24*sin(29) ..... exact value

x = 11.635430885912 .... approximate value

x = 11.6

To get the approximate value, you'll need a calculator. Make sure the calculator is in degree mode.

The answer would be 12.
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