Question

como resolver
x+6y=3
x-y=-9

Answer 1

x + 6y = 3
x - y = - 9 *(- 1)
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x + 6y = 3
- x + y = 9
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7y = 12
y = 12/7

x - y = - 9
x = - 9 + y
x = - 9 + 12/7 mmc = 7
x = (- 9.7 + 12)/7
x = (- 63 + 12)/7
x = - 51/7

S = {- 51/7 ; 12/7}