Question

resolva os sistemas abaixo x+y=7 x+2y=11

Answer 1

x + y = 7 .(-2)
x + 2y = 11
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-2x -2y = -14
x + 2y = 11
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-x = - 3 .(-1)
x = 3
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substitui em x + y = 7
3 + y = 7
y = 7 - 3
y = 4
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S= {3, 4}