Đáp án:
`(2x-1)^2-25=0`
`<=>(2x-1-5)(2x-1+5)=0`
`<=>(2x-6)(2x+4)=0`
`<=>(x-3)(x+2)=0`
`<=>` \(\left[ \begin{array}{l}x-3=0\\x+2=0\end{array} \right.\)
`<=>` \(\left[ \begin{array}{l}x=3\\x=-2\end{array} \right.\)
`b)8x^3-50x=0`
`<=>2x(4x^2-25)=0`
`<=>2x(2x-5)(2x+5)=0`
`<=>` \(\left[ \begin{array}{l}2x=0\\2x-5=0\\2x+5=0\end{array} \right.\)
`<=>` \(\left[ \begin{array}{l}x=0\\2x=5\\2x=-5\end{array} \right.\)
`<=>` \(\left[ \begin{array}{l}x=0\\x=\dfrac52\\x=-\dfrac52\end{array} \right.\)
