9514 1404 393
Answer:
(x, y) = (-2, 7)
Explanation:
Add the first equation to twice the second.
(4x +4y) +2(2x -2y) = (20) +2(-18)
8x = -16 . . . . . . simplify
x = -2 . . . . . . . . divide by 8
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2(-2) -2y = -18 . . . . .substitute into the second equation
y + 2 = 9 . . . . . . . . . divide by -2
y = 7 . . . . . . . . . . . subtract 2
The solution is (x, y) = (-2, 7).