a, `7x(x - 10) = 0`
`⇒ x(x - 10) = 0`
`⇒` \(\left[ \begin{array}{l}x = 0\\x - 10 = 0\end{array} \right.\)
`⇒` \(\left[ \begin{array}{l}x = 0\\x = 10\end{array} \right.\)
b, `17(3x - 6)(2x - 8) = 0`
`⇒ (3x - 6)(2x - 8) = 0`
`⇒ 3(x - 2)2(x - 4) = 0`
`⇒ (x - 2)(x - 4) = 0`
`⇒` \(\left[ \begin{array}{l}x - 2 = 0\\x - 4 = 0\end{array} \right.\)
`⇒` \(\left[ \begin{array}{l}x = 2\\x = 4\end{array} \right.\)
c, `(4 - 2x)(x - 3) = 0`
`⇒` \(\left[ \begin{array}{l}4 - 2x = 0\\x - 3 = 0\end{array} \right.\)
`⇒` \(\left[ \begin{array}{l}2x = 4\\x = 3\end{array} \right.\)
`⇒` \(\left[ \begin{array}{l}x = 2\\x = 3\end{array} \right.\)
d, `-x(x + 7)(x - 4) = 0`
`⇒` \(\left[ \begin{array}{l}-x(x + 7) = 0\\x - 4 = 0\end{array} \right.\)
`⇒` $\left[ \begin{array}{l}\left[ \begin{array}{l}x = 0\\x + 7 = 0\end{array} \right.\\x = 4\end{array} \right.$
`⇒` $\left[ \begin{array}{l}\left[ \begin{array}{l}x = 0\\x = -7\end{array} \right.\\x = 4\end{array} \right.$
