xy-2x+y=-3
=>\(\left(xy-2x\right)+\left(y-2\right)=-5\)
=>\(x\left(y-2\right)+\left(y-2\right)=-5\)
=>\(\left(x+1\right)\left(y-2\right)=-5\)
=>\(\left(x+1\right)\cdot\left(y-2\right)=1\cdot\left(-5\right)=\left(-5\right)\cdot1=\left(-1\right)\cdot5=5\cdot\left(-1\right)\)
=>\(\left(x+1;y-2\right)\in\left\{\left(1;-5\right);\left(-5;1\right);\left(-1;5\right);\left(5;-1\right)\right\}\)
=>\(\left(x,y\right)\in\left\{\left(0;-3\right);\left(-6;3\right);\left(-2;7\right);\left(4;1\right)\right\}\)
Ta có : xy - 2x + y = -3
=> x(y - 2) + y - 2 = -3 - 2
=> x(y - 2) + (y - 2) = -5
=> (x + 1)(y - 2) = -5
=> x + 1;y - 2 ∈ Ư(-5) ∈ { -5;-1;1;5}
=>(x + 1 ; y − 2) ∈ { (1;− 5);( −5 ; 1);( −1 ; 5);(5 ; −1) }
=>(x , y) ∈ { (0 ; −3);(−6 ; 3);(−2 ; 7);(4 ; 1) }
