a, 5x ( 3x - 5 ) = 10 - 6x
⇔ 15x² - 25x = 10 - 6x
⇔ 15x² - 25x + 6x - 10 = 0
⇔ 5x ( 3x - 5 ) + 2 ( 3x - 5) = 0
⇔ (3x - 5 )( 5x + 2) = 0
⇔\(\left[ \begin{array}{l}3x -5=0\\5x+2=0\end{array} \right.\)
⇔$\left \{ {{3x=5} \atop {5x=-2}} \right.$
⇔\(\left[ \begin{array}{l}x=\frac{5}{3}\\x=-\frac{2}{5}\end{array} \right.\)
b, (3x - 2)² - 16x² = 0
⇔ (3x - 2 - 4x)( 3x - 2 +4x ) = 0
⇔ (-x-2)(7x - 2) = 0
⇔\(\left[ \begin{array}{l}-x-2=0\\7x-2=0\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=-2\\x=\frac{2}{7}\end{array} \right.\)
