(X+3) . (Y-5)=-25 Tìm số chưa biết trong 1 biểu thức

(x+3)(y-5)=-25

TH1: $\left \{ {{x+3=1} \atop {y-5=-25}} \right.$ =>$\left \{ {{x=-2} \atop {y=-20}} \right.$ 

TH2: $\left \{ {{x+3=-1} \atop {y-5=25}} \right.$ =>$\left \{ {{x=-4} \atop {y=30}} \right.$ 

TH3: $\left \{ {{x+3=25} \atop {y-5=-1}} \right.$ =>$\left \{ {{x=22} \atop {y=4}} \right.$ 

TH4: $\left \{ {{x+3=-25} \atop {y-5=1}} \right.$ =>$\left \{ {{x=-28} \atop {y=6}} \right.$ 

TH5 $\left \{ {{x+3=5} \atop {y-5=-5}} \right.$ =>$\left \{ {{x=2} \atop {y=0}} \right.$ 

TH6 $\left \{ {{x+3=-5} \atop {y-5=5}} \right.$ =>$\left \{ {{x=-8} \atop {y=10}} \right.$ 

Vậy (x,y)∈{-2;-20);(-4;30);(22;4);(-28;6);(2;0);(-8;20)}