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Bạn cần viết đề bằng công thức toán để được hỗ trợ tốt hơn (biểu tượng $\sum$ góc trái khung soạn thảo)
a, -7/2 + 3/4 - 17/2 = (-7/2 - 17/2) + 3/4 = -12 + 3/4 = -45/4 = -12,75.
b, -1/12 - 21/8 + 1/3 = -1/12 + 1/3 - 21/8 = 1/4 - 21/8 = -19/8 = -2,375
\(a,\left(\frac{3}{8}+-\frac{3}{4}+\frac{7}{12}\right):\frac{5}{6}+\frac{1}{2}\)
= \(\left(-\frac{3}{8}+\frac{7}{12}\right):\frac{5}{6}+\frac{1}{2}\)
= \(\frac{5}{24}:\frac{5}{6}+\frac{1}{2}\)
= \(\frac{1}{4}+\frac{1}{2}\)
= \(\frac{3}{4}\)
b)\(-\frac{7}{3}.\frac{5}{9}+\frac{4}{9}.\left(-\frac{3}{7}\right)+\frac{17}{7}\)
=\(-\frac{35}{27}+\left(-\frac{4}{21}\right)+\frac{17}{7}\)
= \(-\frac{35}{27}+\frac{47}{21}\)
= \(\frac{178}{189}\)
c) \(\frac{117}{13}-\left(\frac{2}{5}+\frac{57}{13}\right)\)
= \(\frac{117}{13}-\frac{311}{65}\)
= \(\frac{274}{65}\)
d) \(\frac{2}{3}-0,25:\frac{3}{4}+\frac{5}{8}.4\)
= \(\frac{2}{3}-\frac{1}{4}:\frac{3}{4}+\frac{5}{8}.4\)
= \(\frac{2}{3}-\frac{1}{3}+\frac{5}{2}\)
= \(\frac{1}{3}+\frac{5}{2}\)
= \(\frac{17}{6}\)
\(\left(\frac{2}{3}-\frac{4}{7}\right):\frac{5}{9}+\left(-\frac{8}{7}+\frac{1}{3}\right):\frac{5}{9}\)
\(=\left[\left(\frac{2}{3}-\frac{4}{7}\right)+\left(-\frac{8}{7}+\frac{1}{3}\right)\right]:\frac{5}{9}\)
\(=\left(\frac{2}{3}-\frac{4}{7}-\frac{8}{7}+\frac{1}{3}\right)\cdot\frac{9}{5}\)
\(=\left(1-\frac{12}{7}\right)\cdot\frac{9}{5}\)
\(=-\frac{5}{7}\cdot\frac{9}{5}\)
\(-\frac{9}{7}\)
\(\left(\frac{2}{3}-\frac{4}{7}\right):\frac{5}{9}+\left(-\frac{8}{7}+\frac{1}{3}\right):\frac{5}{9}\)
\(=\left(\frac{14}{21}-\frac{12}{21}\right):\frac{5}{9}+\left(-\frac{24}{21}+\frac{7}{21}\right):\frac{5}{9}\)
\(=\frac{2}{21}:\frac{5}{9}+\frac{-17}{21}:\frac{5}{9}\)
\(=\left(\frac{2}{21}+\frac{-17}{21}\right):\frac{5}{9}\)
\(=\frac{-15}{21}:\frac{5}{9}\)
\(=\frac{-15}{21}.\frac{9}{5}\)
\(=\frac{-9}{7}\)
\(=\frac{99}{35}\)
a) \(\frac{-5}{8}\cdot\frac{11}{3}+\frac{-5}{8}\cdot\frac{1}{3}=-\frac{5}{8}\left(\frac{11}{3}+\frac{1}{3}\right)=-\frac{5}{8}\cdot4=-\frac{5}{2}\cdot1=-\frac{5}{2}\)
b) \(\frac{2}{3}+\frac{3}{4}\cdot\frac{9}{5}=\frac{2}{3}+\frac{27}{20}=\frac{121}{60}\)
c) Tương tự câu a
d) \(\frac{1}{7}\cdot\frac{3}{8}+\frac{1}{7}\cdot\frac{5}{8}=\frac{1}{7}\left(\frac{3}{8}+\frac{5}{8}\right)=\frac{1}{7}\cdot1=\frac{1}{7}\)
\(a,\frac{-5}{8}.\frac{11}{3}+\frac{-5}{8}.\frac{1}{3}\)
\(=\frac{-5}{8}\left(\frac{11}{3}+\frac{1}{3}\right)\)
\(=\frac{-5}{8}.4\)
\(=\frac{-5}{2}\)
\(b,\frac{2}{3}+\frac{3}{4}.\frac{9}{5}\)
\(=\frac{2}{3}+\frac{27}{20}\)
\(=\frac{40}{60}+\frac{81}{60}\)
\(=\frac{121}{60}\)
\(c,\frac{-5}{7}.\frac{4}{9}-\frac{5}{9}.\frac{5}{7}\)
\(=\frac{-5}{7}\left(\frac{4}{9}+\frac{5}{9}\right)\)
\(=\frac{-5}{7}.1\)
\(=\frac{-5}{7}\)
\(d,\frac{1}{7}.\frac{3}{8}+\frac{1}{7}.\frac{5}{8}\)
\(=\frac{1}{7}\left(\frac{3}{8}+\frac{5}{8}\right)\)
\(=\frac{1}{7}.1\)
\(=\frac{1}{7}\)
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