Let's use the "elimination by addition/subtraction" method to solve this system for x and y.
-8x=72-16y
4x=-92+16y <= Mult. all 3 terms by 2: 8x = - 184 + 32y
Now combine the following, column by column:
-8x= 72-16y
8x = - 184 + 32y
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0 = -112 + 16y. Solving for y, 16y = 112, and y = 7.
Now subst. 7 for y in either of the original equations and calculate x:
4x=-92+16(7) => 4x = -92 + 112 = 20. Then x = 5.
Solution is 5, -7 (or, better written) (5, - 7).
