Tìm x: (5x -2)^2 + (2 -5x)(3x +1)=0

Phương pháp:

Phân tích vế trái thành nhân tử chung.

Cách giải:

${\left(5x-2\right)}^2+\left(2-5x\right)\left(3x+1\right)=0\iff {\left(5x-2\right)}^2-\left(5x-2\right)\left(3x+1\right)=0$

$\iff \left(5x-2\right)\left[\left(5x-2\right)-\left(3x+1\right)\right]=0$

$\iff \left(5x-2\right)\left(5x-2-3x-1\right)=0\iff \left(5x-2\right)\left(2x-3\right)=0$

$\iff \left[\begin{array}{l}5x-2=0\\ 2x-3=0\end{array}\right.\iff \left[\begin{array}{l}x=\frac{2}{5}\\ x=\frac{3}{2}\end{array}\right.$