Cộng vế:
\(x^3-y^3+3x^2+3y^2+4x-4y+4=0\)
\(\Leftrightarrow\left(x+1\right)^3-\left(y-1\right)^3+x-y+2=0\)
\(\Leftrightarrow\left(x-y+2\right)\left(x^2+y^2+xy+x-y+2\right)=0\)
\(\Leftrightarrow\left(x-y+2\right)\left[\left(x+\dfrac{y}{2}+\dfrac{1}{2}\right)^2+\dfrac{3}{4}\left(y-1\right)^2+1\right]=0\)
\(\Leftrightarrow y=x+2\)