Question

giải phương trình \(2x^4-9x^3+14x^2-9x+2=0\)

Answer 1

\(2x^4-9x^3+14x^2-9x+2=0\)

\(\Leftrightarrow2x^4-4x^3-5x^3+10x^2+4x^2-8x-x+2=0\)

\(\Leftrightarrow2x^3\left(x-2\right)-5x^2\left(x-2\right)+4x\left(x-2\right)-\left(x-2\right)=0\)

\(\Leftrightarrow\left(x-2\right)\left(2x^3-5x^2+4x-1\right)=0\)

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

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

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

\(\Leftrightarrow\left(x-2\right)\left(x-1\right)\left(x-1\right)\left(2x-1\right)=0\)

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