Question

In order to solve the following system of equations by addition, which of the following could you do before adding the equations so that one variable will be eliminated when you add them? -2x+ 4y= 10 3x- 2y: -7 A. Multiply the top equation by 2 and the bottom equation by 3. B. Multiply the top equation by -3. C. Multiply the bottom equation by 2. D. Multiply the top equation by 3 and the bottom equation by -2.

Answer 1

C. Multiply the bottom equation by 2

x = - 1

y = 2

Explanation:

Multiplying 3x - 2y = - 7 by 2, we get:

- 2x + 4y = 10

6x - 4y = - 14

____________

4x = - 4

x = - 1

Putting x = - 1 in 3x - 2y = - 7, we get:

3 * (- 1) - 2y = - 7

= - 3 - 2y = - 7

= - 2y = - 7 + 3

= - 2y = - 4

= y = 2

Hope this helps!

Answer 2

C. Multiply the bottom equation by 2

Explanation:

-2x+ 4y= 10

3x- 2y =-7

We want to multiply the second equation by 2

-2x+ 4y= 10

6x- 4y =-14

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4x +0y = -4