Question

tìm nghiệm của 2x^3 + x^2 + 2x +1

Answer 1

\(2x^3+x^2+2x+1=0\)

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

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

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

\(\Leftrightarrow x=-\dfrac{1}{2}\)

Answer 2

Ta có: \(2x^3+x^2+2x+1=0\)

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

\(\Leftrightarrow2x+1=0\)

hay \(x=-\dfrac{1}{2}\)