A) -1/39+-1/52
B) -6/9+-12/16
C) -2/5--3/11
D) -34/37 *74/-85
E) -5/9:-7/18
K
Khách
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TM
2
26 tháng 8 2016
\(\frac{-1}{39}+\frac{-1}{52}=\frac{-7}{156}\)
\(\frac{-6}{9}+\frac{12}{16}=\frac{-2}{3}+\frac{3}{4}=\frac{1}{12}\)
\(\frac{-2}{5}-\frac{-3}{11}-\frac{34}{37}-\frac{74}{-85}=\frac{-1215}{6919}\)
\(\frac{-5}{9}:\frac{-7}{18}=\frac{-5}{9}.\frac{-18}{7}=\frac{10}{7}\)
RL
26 tháng 8 2016
-1/39 + -1/52 = -7/156
-6/9 + -12/16 = -17/12
-2/5 - - 3/11 [ (-) + ( -) = +] = -2/5 + 3/11 = -7/55
-34/37 - 74/ -85 = -152/3145
-5/9 : -7/18 = 10/7
31 tháng 3 2021
Bài 1:
a) Ta có: \(\dfrac{2}{5}\cdot x+\dfrac{1}{3}=\dfrac{1}{5}\)
\(\Leftrightarrow\dfrac{2}{5}\cdot x=\dfrac{1}{5}-\dfrac{1}{3}=\dfrac{-2}{15}\)
\(\Leftrightarrow x=\dfrac{-2}{15}:\dfrac{2}{5}=\dfrac{-2}{15}\cdot\dfrac{5}{2}\)
hay \(x=-\dfrac{1}{3}\)
Vậy: \(x=-\dfrac{1}{3}\)
b) Ta có: \(\dfrac{1}{5}+\dfrac{5}{3}:x=\dfrac{1}{2}\)
\(\Leftrightarrow\dfrac{5}{3}:x=\dfrac{1}{2}-\dfrac{1}{5}=\dfrac{3}{10}\)
\(\Leftrightarrow x=\dfrac{5}{3}:\dfrac{3}{10}=\dfrac{5}{3}\cdot\dfrac{10}{3}\)
hay \(x=\dfrac{50}{9}\)
Vậy: \(x=\dfrac{50}{9}\)
c) Ta có: \(\dfrac{4}{9}-\dfrac{5}{3}\cdot x=-2\)
\(\Leftrightarrow\dfrac{5}{3}x=\dfrac{4}{9}+2=\dfrac{22}{9}\)
\(\Leftrightarrow x=\dfrac{22}{9}:\dfrac{5}{3}=\dfrac{22}{9}\cdot\dfrac{3}{5}\)
hay \(x=\dfrac{22}{15}\)
Vậy: \(x=\dfrac{22}{15}\)
d) Ta có: \(\dfrac{5}{7}:x-3=\dfrac{-2}{7}\)
\(\Leftrightarrow\dfrac{5}{7}:x=\dfrac{-2}{7}+3=\dfrac{19}{21}\)
\(\Leftrightarrow x=\dfrac{5}{7}:\dfrac{19}{21}=\dfrac{5}{7}\cdot\dfrac{21}{19}\)
hay \(x=\dfrac{15}{19}\)
Vậy:\(x=\dfrac{15}{19}\)
NC
2
DH
24 tháng 6 2017
\(\dfrac{-1}{39}+\dfrac{-1}{52}=\dfrac{-7}{156}\)
\(\dfrac{-6}{9}+\dfrac{-12}{16}=\dfrac{-17}{12}\)
\(\dfrac{-2}{5}-\dfrac{-3}{11}=\dfrac{-7}{55}\)
\(\dfrac{-34}{37}.\dfrac{74}{-85}=\dfrac{4}{5}\)
\(\dfrac{-5}{9}:\dfrac{-7}{18}=\dfrac{10}{7}\)
Chúc bạn học tốt!!!
Q
24 tháng 6 2017
a) \(\left(-\dfrac{1}{39}\right)+\left(-\dfrac{1}{52}\right)=\dfrac{-4-3}{156}=-\dfrac{7}{156}\)
b) \(\left(-\dfrac{6}{9}\right)+\left(-\dfrac{12}{16}\right)=-\dfrac{6}{9}-\dfrac{12}{16}=-\dfrac{17}{12}\)
c) \(-\dfrac{2}{5}-\left(-\dfrac{3}{11}\right)=-\dfrac{2}{5}+\dfrac{3}{11}=-\dfrac{7}{55}\)
d) \(\left(-\dfrac{34}{37}\right)\cdot\left(-\dfrac{74}{85}\right)=2\cdot\dfrac{2}{5}=\dfrac{4}{5}\)
e) \(\left(-\dfrac{5}{9}\right):\left(-\dfrac{7}{18}\right)=\dfrac{5}{9}\cdot\dfrac{18}{7}=5\cdot\dfrac{2}{7}=\dfrac{10}{7}\)
9 tháng 6 2017
a) \(\dfrac{-1}{39}+\dfrac{-1}{52}=\dfrac{-4}{156}+\dfrac{-3}{156}=\dfrac{-7}{156}\)
b) \(\dfrac{-6}{9}+\dfrac{-12}{16}=\dfrac{-2}{3}+\dfrac{-3}{4}=\dfrac{-8}{12}+\dfrac{-9}{12}=\dfrac{-17}{12}\)
c) \(\dfrac{-2}{5}-\dfrac{-3}{11}=\dfrac{-22}{55}-\dfrac{-15}{55}=\dfrac{-7}{55}\)
d) \(\dfrac{-34}{37}.\dfrac{74}{-85}=\dfrac{4}{5}\)
e) \(\dfrac{-5}{9}:\dfrac{-7}{18}=\dfrac{-5}{9}.\dfrac{18}{-7}=\dfrac{10}{7}\)
AH
1 tháng 7 2018
a) \(\frac{-34}{37}\)\(\times\frac{74}{-85}\)\(\frac{-34}{37}\times\frac{74}{-85}=\frac{-34\times74}{37\times\left(-85\right)}=\frac{-34\times2}{1\times\left(-85\right)}=\frac{34}{85}\)
b) \(\frac{-5}{9}:\frac{-7}{18}=\frac{-5}{9}\times\frac{-18}{7}=\frac{-4\times\left(-18\right)}{9\times7}=\frac{-4\times\left(-2\right)}{1\times7}=\frac{8}{7}\)
h cho minh nha
a= -7/156
b=1/12
c=-7/55
d=17/21
e=10/7
cho minh nhé