Question

Tìm x:\(2x^3+x=51x\)

Answer 1

Ta có: \(2x^3+x=51x\)

\(\Leftrightarrow2x^3-50x=0\)

\(\Leftrightarrow2x\left(x-5\right)\left(x+5\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=5\\x=-5\end{matrix}\right.\)

Answer 2

`2x^3+x=51x`

`->2x^2+x-51x=0`

`->2x^2-50x=0`

`->2x(x-25)=0`

`->`\(\left[\begin{array}{} 2x=0\\ x-25=0 \end{array} \right.\)

`->`\(\left[\begin{array}{} x=0\\ x=25 \end{array} \right.\)

Vậy `S={0;25}`

Answer 3

`2x^3+x=51x`

`=>2x^3+x-51x=0`

`<=>2x^3-50x=0`

`<=>2x(x^2-25)=0`

`<=>2x(x-5)(x+5)=0`

`<=>` $\left[\begin{matrix}2x=0\\x-5=0\\x+5=0\end{matrix}\right.$

`<=>` $\left[\begin{matrix}x=0\\x=5\\x=-5\end{matrix}\right.$