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a) \(\dfrac{2\cdot7\cdot13}{26\cdot35}=\dfrac{2\cdot7\cdot13}{2\cdot13\cdot5\cdot7}=\dfrac{1}{5}\)

b) \(\dfrac{31\cdot7-13}{4-35}=\dfrac{217-13}{-31}=\dfrac{-204}{31}\)

c) \(\dfrac{32\cdot7-32\cdot4}{38-35}=\dfrac{32\cdot\left(7-4\right)}{3}=\dfrac{32\cdot3}{3}=32\)

d) \(\dfrac{1717-101}{2828+202}=\dfrac{1616}{3030}=\dfrac{8}{15}\)

e) \(\dfrac{3\cdot6+2\cdot9\cdot5-18\cdot\left(-4\right)}{7\cdot\left(-7\right)+12\cdot\left(-7\right)+7}\)

\(=\dfrac{18+18\cdot5+18\cdot4}{7\cdot\left(-7\right)-12\cdot7+7}\)

\(=\dfrac{18\cdot\left(1+5+4\right)}{7\cdot\left(-7-12+1\right)}\)

\(=\dfrac{18\cdot10}{7\cdot\left(-18\right)}\)

\(=\dfrac{-10}{7}\)

28 tháng 12 2019

a)  − 7 .3 + 4. − 6 − 5 .3 + 2.3 = − 45 = 9 = 6

b)  3.6 + 2.9.5 − 18. − 4 7. − 7 + 12. − 7 + 7 = 18. 1 + 5 + 4 − 7 . 7 + 12 − 1 = 18.10 − 7.18 = − 10 7

12 tháng 4 2020

a) 5

b) -10/7

c) 1/9

19 tháng 2 2017

\(\frac{3.6+2.9.5-18.\left(-4\right)}{7.\left(-7\right)+12.\left(-7\right)+7}=\frac{18+18.5-18.\left(-4\right)}{\left(-7\right).\left(7+12\right)+7}\)

\(=\frac{18\left[1+5-\left(-4\right)\right]}{\left(-7\right).19+7}=\frac{18.10}{7.\left(-19\right)+7}\)

\(=\frac{180}{7\left[\left(-19\right)+1\right]}=\frac{180}{-126}=\frac{=10}{7}\)

3 tháng 3 2017

a) \(\frac{3.6+2.9.5+18.\left(-4\right)}{7.\left(-7\right)+12.\left(-7\right)+7}\)=\(\frac{18+18.5+18.\left(-4\right)}{-7.\left(7+12-1\right)}\)=\(\frac{18.\left(1+5-4\right)}{-7.18}\)=\(\frac{18.2}{18.\left(-7\right)}=\frac{-2}{7}\)

b) \(\frac{2.3.4.5.6-3.4.5.6.7}{2.4.6-4.6.8}=\frac{3.4.5.6.\left(2-7\right)}{4.6.\left(2-8\right)}\)=\(\frac{3.5.\left(-5\right)}{\left(-6\right)}=\frac{-25}{-2}=\frac{25}{2}\)

3 tháng 3 2017

a)\(\frac{3.6+2.9.5+18.\left(-4\right)}{7.\left(-7\right)+12.\left(-7\right)+7}\)

\(=\frac{18+18.5+18.\left(-4\right)}{7.\left(-7\right)+\left(-12\right).7+7}\)

\(=\frac{18.\left(1+5+-4\right)}{7.\left(-7+-12+1\right)}\)

\(=\frac{15.2}{7.\left(-18\right)}\)

\(=\frac{3.5.2}{7.2.3.-3}\)

\(=\frac{5}{-21}\)

b) \(\frac{2.3.4.5.6-3.4.5.6.7}{2.4.6-4.6.8}\)

\(=\frac{3.4.5.6.\left(2-7\right)}{4.6.\left(2-8\right)}\)

\(=\frac{3.4.5.6.\left(-5\right)}{4.6.\left(-3\right)}\)

\(=\frac{3.5.\left(-5\right)}{\left(-3\right)}\)

\(=\frac{-75}{\left(-3\right)}\)

\(=25\)

14 tháng 5 2017

3/5

- 2/3

4/39

26/45

1/12

-29/21