Question

tìm x 

d) ( 4x - 1 ) ² - ( x+7)² = 0

Answer 1

\(< =>\left(4x-1+x+7\right)\left(4x-1-x-7\right)=0< =>\left(5x+6\right)\left(3x-8\right)=0< =>\left\{{}\begin{matrix}5x+6=0\\3x-8=0\end{matrix}\right.< =>\left[{}\begin{matrix}x=-\dfrac{6}{5}\\x=\dfrac{8}{3}\end{matrix}\right.\)

Answer 2

 (4x-1+x+7)(4x-1-x-7)= 0

(5x+6)(3x-8)= 0

=> 5x+6=0 hoặc 3x-8=0

=> x=1,2 hoặc x=8/3

vậy x= 1,2 hoặc x=8/3