a. (4x-10)(24+5x)=0
⇔2(2x-5)(24+5x)=0
⇔\(\left[ \begin{array}{l}2x-5=0\\24+5x=0\end{array} \right.\)⇔\(\left[ \begin{array}{l}x=\frac{5}{2}\\x=\frac{-24}{5}\end{array} \right.\)
Vậy S={$\frac{5}{2}$;$\frac{-24}{5}$}
b. (x-1)(5x+3)=(3x-8)(x-1)
⇔5x²+3x-5x-3=3x²-3x-8x+8
⇔2x²+9x-11=0
⇔(2x²-2x)+(11x-11)=0
⇔(x-1)(2x+11)=0
⇔\(\left[ \begin{array}{l}x-1=0\\2x+11=0\end{array} \right.\)⇔\(\left[ \begin{array}{l}x=1\\x=\frac{-11}{2}\end{array} \right.\)
Vậy S={1;$\frac{-11}{2}$}.