Đáp án đúng: C
Giải chi tiết:\(\begin{array}{l}\,\,\,\,\,82 \times 120 - 20 \times 82\\C1:\,82 \times 120 - 20 \times 82 = \,9\,840 - 1\,640\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \,\,8\,200\\C2:\,82 \times 120 - 20 \times 82 = 82 \times \left( {120 - 20} \right)\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = 82 \times \,\,\,\,\,\,100\\\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\, = \,8\,200\end{array}\)
Chọn C
