Question

1) {X+y = 7
{X-y = 2

Answer 1

Vamos lá.
1)x+y=7
2)x-y=2
2)x=y+2

1)y+2+y=7
2y=7-2
2y=5
y=5/2

x=y+2
x=5/2+2 o mmc de 2,1=2
x=5/2+4/1
x=9/2

S={x=9/2 e y=5/2}

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