Thì thôi t ủng hộ cách làm,thấy bạn kia làm ngán quá :v
\(x^2-y^2+2x-4y-10=0\)
\(\Rightarrow\left(x^2+2x+1\right)-\left(y^2+4y+4\right)-7=0\)
\(\Rightarrow\left(x+1\right)^2-\left(y+2\right)^2=7\)
\(\Rightarrow\left(x+1+y+2\right)\left(x+1-y-2\right)=7\)
\(\Rightarrow\left(x+y+3\right)\left(x-y-1\right)=7\)
Dễ thấy: \(7=1.7=7.1=\left(-1\right).\left(-7\right)=\left(-7\right).\left(-1\right)\)
Dễ r :v