Đáp án đúng: C
Giải chi tiết:\({\rm{ }}\left( {2x - 6} \right)\left( {3x - 18} \right) = 0\)
\( \Rightarrow 2x - 6 = 0\) hoặc \(3x - 18 =0\)
+) Trường hợp 1:
\(\eqalign{& 2x - 6 = 0 \cr & 2x\,\,\,\,\,\,\,\,\,\, = 0 + 6 \cr & 2x\,\,\,\,\,\,\,\,\,\, = 6 \cr & \,\,\,x\,\,\,\,\,\,\,\,\,\, = 6:2 \cr & \,\,\,x\,\,\,\,\,\,\,\,\,\, = 3 \cr} \)
+) Trường hợp 2:
\(\eqalign{& 3x - 18 = 0 \cr & 3x\,\,\,\,\,\,\,\,\,\,\,\,\, = 0 + 18 \cr & 3x\,\,\,\,\,\,\,\,\,\,\,\,\, = 18 \cr & \,\,x\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 18:3 \cr & \,\,x\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 6 \cr} \)
vậy \(x = 3\) hoặc \(x =6\).