Question

Tìm x X^3+4x^2+4x+3=0

Answer 1

Answer 2

`x^3+4x^2+4x+3=0`

`<=>x^3+(x^2+3x^2)+(x+3x)+(1+3)=0`

`<=>(x^3+x^2+x)+(3x^2+3x+3)=0`

`<=>x(x^2+x+1)+3(x^2+x+1)=0`

`<=>(x+3)(x^2+x+1)=0`

`<=>x+3=0\ (x^2+x+1>0\ forall x)`

`<=>x=-3`

Answer 3

\(x^3+4x^2+4x+3=0\)

\(\Leftrightarrow x^3+3x^2+x^2+4x+3=0\)

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

\(\Leftrightarrow x+3=0\)

hay x=-3