a, \(x^2-3x+2=x^2-2x-x+2\)
\(=x.\left(x-2\right)-\left(x-2\right)=\left(x-2\right)\left(x-1\right)\)
b, \(x^2+x-6=x^2+2x-3x-6\)
\(=x.\left(x+2\right)-3.\left(x+2\right)=\left(x+2\right)\left(x-3\right)\)
c, \(x^2+5x+6=x^2+2x+3x+6\)
\(=x.\left(x+2\right)+3\left(x+2\right)=\left(x+2\right)\left(x+3\right)\)
Chúc bạn học tốt!!!