Tính nhanh 2/5×3/7+3/7×3/5×3 5/3×4/5-4/5×1/3×4/5×2/3 31/07/2021 Bởi Mary Tính nhanh 2/5×3/7+3/7×3/5×3 5/3×4/5-4/5×1/3×4/5×2/3
` 2/5 × 3/7 + 3/7 × 3/5 × 3 ` ` = 3/7 × (2/5 + 3/5) × 3 ` ` = 3/7 × 1 × 3 ` ` = 9/7 ` ` 5/3 × 4/5 – 4/5 × 1/3 + 4/5 × 2/3 ` (Sửa đề) ` = 4/5 × (5/3 – 1/3 + 2/3) ` ` = 4/5 × 2 ` ` = 8/5 ` Bình luận
Đáp án: $\dfrac{176}{35}$ Giải thích các bước giải: Sửa đề:$\dfrac{2}{5}×\dfrac{3}{7}+\dfrac{3}{7}×\dfrac{3}{5}+3+\dfrac{5}{3}×\dfrac{4}{5}-\dfrac{4}{5}×\dfrac{1}{3}+\dfrac{4}{5}×\dfrac{2}{3}$ $=\dfrac{3}{7}×(\dfrac{2}{5}+\dfrac{3}{5})+3+\dfrac{4}{5}×(\dfrac{5}{3}-\dfrac{1}{3}+\dfrac{2}{3})$ $=\dfrac{3}{7}×1+3+\dfrac{4}{5}×2$ $=\dfrac{3}{7}+3+\dfrac{8}{5}$ $=\dfrac{15}{35}+\dfrac{105}{35}+\dfrac{56}{35}$ $=\dfrac{15+105+56}{35}$ $=\dfrac{176}{35}$ Bạn xem lại đề xem mình viết đúng chưa nhé Bình luận
` 2/5 × 3/7 + 3/7 × 3/5 × 3 `
` = 3/7 × (2/5 + 3/5) × 3 `
` = 3/7 × 1 × 3 `
` = 9/7 `
` 5/3 × 4/5 – 4/5 × 1/3 + 4/5 × 2/3 ` (Sửa đề)
` = 4/5 × (5/3 – 1/3 + 2/3) `
` = 4/5 × 2 `
` = 8/5 `
Đáp án:
$\dfrac{176}{35}$
Giải thích các bước giải:
Sửa đề:$\dfrac{2}{5}×\dfrac{3}{7}+\dfrac{3}{7}×\dfrac{3}{5}+3+\dfrac{5}{3}×\dfrac{4}{5}-\dfrac{4}{5}×\dfrac{1}{3}+\dfrac{4}{5}×\dfrac{2}{3}$
$=\dfrac{3}{7}×(\dfrac{2}{5}+\dfrac{3}{5})+3+\dfrac{4}{5}×(\dfrac{5}{3}-\dfrac{1}{3}+\dfrac{2}{3})$
$=\dfrac{3}{7}×1+3+\dfrac{4}{5}×2$
$=\dfrac{3}{7}+3+\dfrac{8}{5}$
$=\dfrac{15}{35}+\dfrac{105}{35}+\dfrac{56}{35}$
$=\dfrac{15+105+56}{35}$
$=\dfrac{176}{35}$
Bạn xem lại đề xem mình viết đúng chưa nhé