Câu hỏi của Minh Đặng

Question

Làm hộ bài 3 đi

꧁_͏ͥ͏_͏ͣ͏_͏ͫ͏ ¡亗ᵛᶰシ๖ۣۜT๖ۣۜR๖ۣۜÂ๖ۣ... · Accepted Answer

Bài 3:a) $\dfrac{3}{4}.\dfrac{16}{9}-\dfrac{7}{5}:\dfrac{-21}{20}=\dfrac{4}{3}-\dfrac{-4}{3}=\dfrac{8}{3}$  b) $2\dfrac{1}{3}-\dfrac{1}{3}.\left[\dfrac{-3}{2}+\left(\dfrac{2}{3}+0,4.5\right)\right]$ $=\dfrac{7}{3}-\dfrac{1}{3}.\left[\dfrac{-3}{2}+\left(\dfrac{2}{3}+\dfrac{2}{5}.5\right)\right]$ $=\dfrac{7}{3}-\dfrac{1}{3}.\left[\dfrac{-3}{2}+\left(\dfrac{2}{3}+2\right)\right]$$=\dfrac{7}{3}-\dfrac{1}{3}.\left[\dfrac{-3}{2}+\dfrac{8}{3}\right]$ $=\dfrac{7}{3}-\dfrac{1}{3}.\dfrac{7}{6}$ $=\dfrac{7}{3}-\dfrac{7}{18}$ $=\dfrac{35}{18}$ c) $\left(20+9\dfrac{1}{4}\right):2\dfrac{1}{4}=\left(20+\dfrac{37}{4}\right):\dfrac{9}{4}=\dfrac{117}{4}:\dfrac{9}{4}=13$ d) $\left(6-2\dfrac{4}{5}\right).3\dfrac{1}{8}-1\dfrac{3}{5}:\dfrac{1}{4}$ $=\left(6-\dfrac{14}{5}\right).\dfrac{25}{8}-\dfrac{8}{5}:\dfrac{1}{4}$ $=\dfrac{16}{5}.\dfrac{25}{8}-\dfrac{32}{5}$ $=10-\dfrac{32}{5}$ $=\dfrac{18}{5}$ e) $\dfrac{32}{15}:\left(-1\dfrac{1}{5}+1\dfrac{1}{3}\right)=\dfrac{32}{15}:\left(\dfrac{-6}{5}+\dfrac{4}{3}\right)=\dfrac{32}{15}:\dfrac{2}{15}=16$ g) $0,2.\dfrac{15}{36}-\left(\dfrac{2}{5}+\dfrac{2}{3}\right):1\dfrac{1}{5}$ $=\dfrac{1}{5}.\dfrac{5}{12}-\dfrac{16}{15}:\dfrac{6}{5}$ $=\dfrac{1}{12}-\dfrac{8}{9}$ $=\dfrac{-29}{36}$ h) $1\dfrac{13}{15}.0,75-\left(\dfrac{8}{15}+0,25\right).\dfrac{24}{27}$ $=\dfrac{28}{15}.\dfrac{3}{4}-\left(\dfrac{8}{15}+\dfrac{1}{4}\right).\dfrac{8}{9}$ $=\dfrac{7}{5}-\dfrac{47}{60}.\dfrac{8}{9}$ $=\dfrac{7}{5}-\dfrac{94}{135}$ $=\dfrac{19}{27}$ g) $5:\left(4\dfrac{3}{4}-1\dfrac{25}{28}\right)-1\dfrac{3}{8}:\left(\dfrac{3}{8}+\dfrac{9}{20}\right)$ $=5:\left(\dfrac{19}{4}-\dfrac{53}{28}\right)-\dfrac{11}{8}:\dfrac{33}{40}$ $=5:\dfrac{20}{7}-\dfrac{5}{3}$ $=\dfrac{7}{4}-\dfrac{5}{3}$ $=\dfrac{1}{12}$Câu trả lời: Bài 3:a) $\dfrac{3}{4}.\dfrac{16}{9}-\dfrac{7}{5}:\dfrac{-21}{20}=\dfrac{4}{3}-\dfrac{-4}{3}=\dfrac{8}{3}$  b) $2\dfrac{1}{3}-\dfrac{1}{3}.\left[\dfrac{-3}{2}+\left(\dfrac{2}{3}+0,4.5\right)\right]$ $=\dfrac{7}{3}-\dfrac{1}{3}.\left[\dfrac{-3}{2}+\left(\dfrac{2}{3}+\dfrac{2}{5}.5\right)\right]$ $=\dfrac{7}{3}-\dfrac{1}{3}.\left[\dfrac{-3}{2}+\left(\dfrac{2}{3}+2\right)\right]$$=\dfrac{7}{3}-\dfrac{1}{3}.\left[\dfrac{-3}{2}+\dfrac{8}{3}\right]$ $=\dfrac{7}{3}-\dfrac{1}{3}.\dfrac{7}{6}$ $=\dfrac{7}{3}-\dfrac{7}{18}$ $=\dfrac{35}{18}$ c) $\left(20+9\dfrac{1}{4}\right):2\dfrac{1}{4}=\left(20+\dfrac{37}{4}\right):\dfrac{9}{4}=\dfrac{117}{4}:\dfrac{9}{4}=13$ d) $\left(6-2\dfrac{4}{5}\right).3\dfrac{1}{8}-1\dfrac{3}{5}:\dfrac{1}{4}$ $=\left(6-\dfrac{14}{5}\right).\dfrac{25}{8}-\dfrac{8}{5}:\dfrac{1}{4}$ $=\dfrac{16}{5}.\dfrac{25}{8}-\dfrac{32}{5}$ $=10-\dfrac{32}{5}$ $=\dfrac{18}{5}$ e) $\dfrac{32}{15}:\left(-1\dfrac{1}{5}+1\dfrac{1}{3}\right)=\dfrac{32}{15}:\left(\dfrac{-6}{5}+\dfrac{4}{3}\right)=\dfrac{32}{15}:\dfrac{2}{15}=16$ g) $0,2.\dfrac{15}{36}-\left(\dfrac{2}{5}+\dfrac{2}{3}\right):1\dfrac{1}{5}$ $=\dfrac{1}{5}.\dfrac{5}{12}-\dfrac{16}{15}:\dfrac{6}{5}$ $=\dfrac{1}{12}-\dfrac{8}{9}$ $=\dfrac{-29}{36}$ h) $1\dfrac{13}{15}.0,75-\left(\dfrac{8}{15}+0,25\right).\dfrac{24}{27}$ $=\dfrac{28}{15}.\dfrac{3}{4}-\left(\dfrac{8}{15}+\dfrac{1}{4}\right).\dfrac{8}{9}$ $=\dfrac{7}{5}-\dfrac{47}{60}.\dfrac{8}{9}$ $=\dfrac{7}{5}-\dfrac{94}{135}$ $=\dfrac{19}{27}$ g) $5:\left(4\dfrac{3}{4}-1\dfrac{25}{28}\right)-1\dfrac{3}{8}:\left(\dfrac{3}{8}+\dfrac{9}{20}\right)$ $=5:\left(\dfrac{19}{4}-\dfrac{53}{28}\right)-\dfrac{11}{8}:\dfrac{33}{40}$ $=5:\dfrac{20}{7}-\dfrac{5}{3}$ $=\dfrac{7}{4}-\dfrac{5}{3}$ $=\dfrac{1}{12}$

Thanh Quân · Answer

$a$) $\dfrac{3}{4}.\dfrac{16}{9}-\dfrac{7}{5}:\dfrac{-21}{20}$$=\dfrac{4}{3}-\dfrac{7}{5}.\dfrac{-20}{21}$$=\dfrac{4}{3}-\dfrac{-4}{3}$$=\dfrac{8}{3}$$=2\dfrac{2}{3}$Câu trả lời: $a$) $\dfrac{3}{4}.\dfrac{16}{9}-\dfrac{7}{5}:\dfrac{-21}{20}$$=\dfrac{4}{3}-\dfrac{7}{5}.\dfrac{-20}{21}$$=\dfrac{4}{3}-\dfrac{-4}{3}$$=\dfrac{8}{3}$$=2\dfrac{2}{3}$

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