We will use the elimination by addition/subtraction method to solve for y:
Given 2x - 2y = -20 and -2x + 4y = 14, add the second equation to the first:
2x - 2y = -20
-2x + 4y = 14
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2y = -6. Solving for y: y = -3.
Find x by subst. y=-3 into either of the given equations.
If we choose the first equation, then it becomes 2x - 2(-3) = -20
Solve this for x: 2x + 6 = -20, or 2x = -26, or x = -13.
The solution is (-13,-3).