TH1: (2y+1)^2=9 và (2x+2y)^2=0
=>x+y=0 và \(2y+1\in\left\{3;-3\right\}\)
=>\(\left(x,y\right)\in\left\{\left(-1;1\right);\left(2;-2\right)\right\}\)
TH2: (2y+1)^2=0 và (2x+2y)^2=9
=>\(\left(2y+1;2x+2y\right)\in\left\{\left(0;3\right);\left(0;-3\right)\right\}\)
=>\(\left(x,y\right)\in\left\{\left(-\dfrac{1}{2};2\right);\left(-\dfrac{1}{2};-1\right)\right\}\)