Question

x + y = 7

x + 2y = -5

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Considerando U = N x N.

Answer 1

x = 7-y
x+2y= -5
7-y+2y=-5
-y+2y= -5-7
y = -12

x= 7-y
x= 7-(-12)
x= 7+12
x= +19

S = (19, -12)