Elimination using addition and subtraction.

-4x+4y=-20

-2x+4y=-2

I would subtract the 2nd from the first one

so - 4x - - 2x = - 2x

4y - 4y = 0

-20 - - 2 = - 18

-2x = - 18

now I would divide that by - 2 to get the value for x

so no we have x = 9

now you just have to substitute that into one of the equations and simplify to get y

-2 X 9 + 4y = - 2

-18 + 4y = - 2

4y = 16

y = 4

For addition:

-4x+4y=-20 (multiply by - 1) to get 4x-4y=20

-2x+4y=-2 (Leave as it is) to get - 2x+4y=-2

Add together to eliminate the y term

Solve for x (x=9)

Plug in x to either equation to get y (y=4)

Answer: (9,4)

For subtraction:

-4x+4y=-20

-2x+4y=-2

Since the equations are already ready for elimination by subtraction, just Subtract to eliminate the y term

Solve for x (x=9)

Plug in x to either equation to get y (y=4)

Answer: (9,4)