Giải phương trình 3x(25x+15)-35(5x+3)=0

* Hướng dẫn giải

$3x\left(25x+15\right)-35\left(5x+3\right)=0\iff 5.3x\left(5x+3\right)-35\left(5x+3\right)=0$

$\left(5x+3\right)\left(15x-35\right)=0\iff \left[\begin{array}{l}5x+3=0\\ 15x-35=0\end{array}\right.\iff \left[\begin{array}{l}x=-\frac{3}{5}\\ x=\frac{7}{3}\end{array}\right.$