Question

tính

(x-1)(x+1)(x+2)

Answer 1

\(\left(x-1\right)\left(x+1\right)\left(x+2\right)=\left(x^2-1\right)\left(x+2\right)\)

\(=x^3-x+2x^2-2\)

Answer 2

\(\left(x-1\right)\left(x+1\right)\left(x+2\right)=0\)

\(=>\left(x^2-1\right)\left(x+2\right)=0\)

\(=>\orbr{\begin{cases}x^2-1=0\\x+2=0\end{cases}}\)

\(=>\orbr{\begin{cases}x=-1;1\\x=-2\end{cases}}\)

T nha các bạn