Question

Tìm x , biết:

8x³ + 8x² + 2x =0

Answer 1

\(8x^3+8x^2+2x=0\)

\(\Rightarrow2x\left(4x^2+4x+1\right)=0\)

\(\Rightarrow2x\left[\left(2x\right)^2+2.x.2+1^2\right]=0\)

\(\Rightarrow2x\left(2x+1\right)^2=0\)

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

\(\Rightarrow\left[{}\begin{matrix}x=0\\2x+1=0\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=0\\x=-\dfrac{1}{2}\end{matrix}\right.\)

Vậy........................................