Question

8x^3 - 2x = 0
giai

Answer 1

8x³ -2x = 0

2x(4x² - 1) = 0

2x = 0 ⇒ x = 0

4x² = 1 ⇒ x = +- 1/2

x ∈ {-1/2; 0;1/2}

Answer 2

`8x^3 - 2x = 0`

`<=> 2x(4x^2-1) =0`

`<=> 2x(2x-1).(2x+1)`

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

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

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

vậy `S=  {0;1/2;-1/2}`