\(\Leftrightarrow\left(x-4\right)\left(x+\dfrac{6}{5}\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=4\\x=\dfrac{-6}{5}\end{matrix}\right.\)
Vậy pt có nghiệm là S=\(\left\{4;\dfrac{-6}{5}\right\}\)
=>5y^2-14y-24=0
=>5y^2-20y+6y-24=0
=>(y-4)(5y+6)=0
=>y=-6/5 hoặc y=4