Question

[Pham hung cuong]

Tim cac so nguyen x,y thoa man : xy+3x-y=8

Answer 1

[Đinh quang hiệp]

\(xy+3x-y=8\Rightarrow xy+3x-y-3=5\Rightarrow x\left(y+3\right)-\left(y+3\right)=\left(x-1\right)\left(y+3\right)=5\)

\(\Rightarrow\left(x-1\right)\left(y+3\right)=1\cdot5=5\cdot1=\left(-1\right)\cdot\left(-5\right)=\left(-5\right)\cdot\left(-1\right)=5\)

nếu x-1=1 suy ra x=2 thì y+3=5 suy ra y=2

      x-1=5 suy ra x=6 thì y+3=1 suy ra y=-2

      x-1=-1 suy ra x=0 thì y+3=-5 suy ra y=-8

      x-1=-5 suy ra x=-4 thì y+3=-1 suy ra y--4

vậy x=2 thì y=2;x=6 thì y=-2;x=0 thì y=-8;x=-4 thì y=-4

Answer 2

[Pham hung cuong]

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