Question

Can some one refresh my memory on how to do this

Answer 1

11.

3x - 2y = 2

5x - 5y = 10

We can divide the second one by 5,

x - y = 2

and multiply by 2,

2x - 2y = 4

Subtracting from the first equation,

3x - 2y - (2x - 2y) = 2 - 4

x = -2

y = x - 2 = -4

Check:

3x - 2y = 3(-2) - 2(-4) = -6 + 8 = 2 good

5x - 5y = 5(-2) - 5(-4) = -10 + 20 = 10 good

Answer: x=-2, y=-4

12. Factor

First we take out the common factor of 2. Then we need two numbers that add to 11 and multiply to 30; that's 5 and 6.

$2k^2 + 22k + 60 = 2(k^2 + 11k + 30)=2(k+5)(k+6)$

Answer: 2(k+5)(k+6)

13.

5x+3y = -15 Solve for x given y=0

5x+3(0)=-15

5x = -15

x = -15/5 = -3

Answer: -3