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3 years ago

Please help me on this question I really need help. :,)

Mathematics

1 answer:

Kazeer [188]3 years ago

6 0

Answer:

a. (7, 27) Polly was incorrect.

b. (3, 1) Polly was correct.

Step-by-step explanation:

y = 4x - 1

2x - y = -13

We can solve this by substitution. Our first equation gives us y. Plug that into our second equation for each instance of y.

2x - y = -13

2x - (4x - 1) = -13

First distribute the negative sign across the parentheses.

2x - 4x + 1 = -13

Combine like terms.

-2x + 1 = -13

-2x = -14

Divide both sides by -2.

x = 7

Now that we know x, plug its value into one of our original equations.

y = 4x - 1

y = 4(7) - 1

Solve.

y = 28 - 1

y = 27

Our solution is (7, 27).

Let's check our answer by plugging both values into one of our original equations.

2x - y = -13

2(7) - 27 = -13

Solve.

14 - 27 = -13

-13 = -13

Your solution is correct.

Polly's solution was (-2, -9), which is incorrect.

3x + 6y = 15

-2x + 3y = -3

Let's solve this by elimination. To solve by elimination means to eliminate a variable from the equation.

We have 3x & -2x and 6y & 3y. Notice that 6 and 3 can be simplified easily. To eliminate y, we want to multiply each factor of the second equation by -2.

-2x + 3y = -3

-2(-2x + 3y = -3)

4x - 6y = 6

Write the equations together.

3x + 6y = 15

4x - 6y = 6

Now we can see that the y variable will cancel out.

Apply the elimination method.

3x + 6y = 15

4x - 6y = 6

________

7x = 21

Divide both sides by 7.

x = 3

Now that we know x, plug its value into one of our original equations.

3x + 6y = 15

3(3) + 6y = 15

Solve.

9 + 6y = 15

6y = 15 - 9

6y = 6

y = 1

Our solution is (3, 1).

Let's check our answer by plugging both values into one of our original equations.

-2x + 3y = -3

-2(3) + 3(1) = -3

Solve.

-6 + 3 = -3

-3 = -3

Your solution is correct.

Polly's solution was (3, 1), so she was correct.

Hope this helps!

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Answer:

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4x−7+31=4x+2

Step 1: Simplify both sides of the equation.

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