Trang chủ » Hỏi đáp » Môn Toán a . 2/3 × 1/9-2/5× 4/3 b. 3/7 × (-5/12) +6/12 ×3/7 06/05/2024 a . 2/3 × 1/9-2/5× 4/3 b. 3/7 × (-5/12) +6/12 ×3/7
Giải đáp: a) \frac{2}{3}xx\frac{1}{9}-\frac{2}{5}xx\frac{4}{3} =\frac{2}{3}xx\frac{1}{9}-\frac{2}{5}xx2xx\frac{2}{3} =\frac{2}{3}xx\frac{1}{9}-\frac{4}{5}xx\frac{2}{3} =\frac{2}{3}xx(\frac{1}{9}-\frac{4}{5}) =\frac{2}{3}xx(\frac{5}{45}-\frac{36}{45}) =\frac{2}{3}xx(-\frac{31}{45}) =-\frac{62}{135} b) \frac{3}{7}xx(-\frac{5}{12})+\frac{6}{12}xx\frac{3}{7} =\frac{3}{7}xx[(-\frac{5}{12})+\frac{6}{12}] =\frac{3}{7}xx\frac{1}{12} =\frac{1}{28} Trả lời
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