Question

[Lê Minh Châu Anh]

Tim x de gia tri cua cac bieu thuc sau =0

a. x^3-x^2-4x-4

b. x^3-x^2+2x-2

c. x^3+6x^2+11x+6

Answer 1

[Nguyễn Lê Phước Thịnh]

b: \(\Leftrightarrow x^2\left(x-1\right)+2\left(x-1\right)=0\)

=>x-1=0

=>x=1

c: \(\Leftrightarrow x^3+x^2+5x^2+5x+6x+6=0\)

\(\Leftrightarrow\left(x+1\right)\left(x^2+5x+6\right)=0\)

\(\Leftrightarrow\left(x+1\right)\left(x+2\right)\left(x+3\right)=0\)

hay \(x\in\left\{-1;-3;-2\right\}\)