Ta có : \(x^2-17x-60\)
\(=x^2+3x-20x-60\)
\(=x\left(x+3\right)-20\left(x+3\right)\)
\(=\left(x-20\right)\left(x+3\right)\)
\(x^2-17x-60\)
\(=x^2-20x+3x-60\)
\(=x.\left(x-20\right)+3.\left(x-20\right)\)
\(=\left(x-20\right).\left(x+3\right)\)
Chúc bạn học tốt !! :))))