Question

Tìm x:

a,x(4x^2-1)=0

b,3(x-1)^2-3x(x-5)-2=0

c,2x^2-5x-7=0

Answer 1

a) x(4x²-1)=0

=>x(2x-1)(2x+1)=0

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

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

vậy x\(\in\) {-\(\dfrac{1}{2}\) ;0;\(\dfrac{1}{2}\) }