Question

Giải phương trình sau:

(2x+1) . (x2+2)=0

Answer 1

( 2x + 1).(2x +2 )=0

\(\Leftrightarrow4x^2+4x+2x+2=0\)

\(\Leftrightarrow4x^2+6x+2=0\)

\(\Leftrightarrow4x^2+4x+2x+2=0\)

\(\Leftrightarrow4x\left(x+1\right)+2\left(x+1\right)=0\)

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

\(\Leftrightarrow\left[{}\begin{matrix}4x+2=0\\x+1=0\end{matrix}\right.\)

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

Vậy phương trình có tập nghiệm S =\(\left\{\dfrac{-1}{2};-1\right\}\)

Answer 2

(2x+1)(x^2+2)=0

=>2x+1=0

=>x=-1/2