Question

Tìm x : x^2-11x-12=0

Answer 1

=>(x-12)(x+1)=0

=>x=12 hoặc x=-1

Answer 2

\(x^2-11x-12=0\\ x^2-12x+x-12=0\\ x\left(x-12\right)+\left(x-12\right)=0\\ \left(x-12\right)\left(x+1\right)=0\\ \left[{}\begin{matrix}x-12=0\\x+1=0\end{matrix}\right.\left[{}\begin{matrix}x=12\\x=-1\end{matrix}\right.\)