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)