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8 tháng 7 2020
Đề bài: Tìm x
\(\frac{2}{3}x-0.4=\frac{1}{5}\)
\(\frac{2}{3}x-0=\frac{1}{5}\)
\(\frac{2}{3}x=\frac{1}{5}\)
\(x=\frac{1}{5}\div\frac{2}{3}\)
\(x=\frac{1}{5}.\frac{3}{2}\)
\(x=\frac{3}{10}\)
Vậy \(x=\frac{3}{10}.\)
NC
8 tháng 7 2020
Bài làm:
\(\frac{2}{3}x-0.4=\frac{1}{5}\)
\(\Leftrightarrow\frac{2}{3}x-\frac{2}{5}=\frac{1}{5}\)
\(\Leftrightarrow\frac{2}{3}x=\frac{3}{5}\)
\(\Leftrightarrow x=\frac{3}{5}\div\frac{2}{3}\)
\(\Rightarrow x=\frac{9}{10}\)
Học tốt!!!!
7 tháng 7 2016
a)Ta có: \(\frac{-2}{5}+\frac{6}{5}.\left(y-\frac{2}{3}\right)=\frac{-4}{15}\)
\(\Rightarrow\frac{6}{5}.\left(y-\frac{2}{3}\right)=\frac{-4}{15}-\frac{-2}{15}\)
\(\Rightarrow\frac{6}{5}.\left(y-\frac{2}{3}=\right)\frac{-2}{5}\)
\(\Rightarrow y-\frac{2}{3}=\frac{-2}{5}:\frac{6}{5}=\frac{-1}{3}\)
\(\Rightarrow y=\frac{-1}{3}+\frac{2}{3}=\frac{1}{3}\)
Vậy x = \(\frac{1}{3}\)
b) Ta có: \(\frac{-2}{5}+\frac{2}{3}x+\frac{1}{6}x=\frac{-4}{15}\)
\(\Rightarrow\frac{-2}{5}+x.\left(\frac{2}{3}+\frac{1}{6}\right)=\frac{-4}{15}\)
\(\Rightarrow x.\frac{5}{6}=\frac{-4}{15}-\frac{-2}{15}\)
\(x.\frac{5}{6}=\frac{-2}{15}\)
\(\Rightarrow x=\frac{-2}{15}:\frac{5}{6}=\frac{-4}{25}\)
Vậy x = \(\frac{-4}{25}\)
c) Ta có: \(\frac{3}{2}x+\frac{-2}{5}-\frac{2}{3}.x=\frac{-4}{15}\)
\(\Rightarrow\frac{3}{2}x-\frac{2}{3}x+\frac{-2}{5}=\frac{-4}{15}\)
\(\Rightarrow x.\left(\frac{3}{2}-\frac{2}{4}\right)=\frac{-4}{15}-\frac{-2}{15}\)
\(\Rightarrow x.\frac{5}{6}=\frac{-2}{15}\)
\(\Rightarrow x=\frac{-2}{15}:\frac{5}{6}=\frac{-4}{25}\)
Vậy x = \(\frac{-4}{25}\)
Ủng hộ tớ nha m.n
12 tháng 4
a)Ta có: \(\frac{- 2}{5} + \frac{6}{5} . \left(\right. y - \frac{2}{3} \left.\right) = \frac{- 4}{15}\)
\(\Rightarrow \frac{6}{5} . \left(\right. y - \frac{2}{3} \left.\right) = \frac{- 4}{15} - \frac{- 2}{15}\)
\(\Rightarrow \frac{6}{5} . \left(\right. y - \frac{2}{3} = \left.\right) \frac{- 2}{5}\)
\(\Rightarrow y - \frac{2}{3} = \frac{- 2}{5} : \frac{6}{5} = \frac{- 1}{3}\)
\(\Rightarrow y = \frac{- 1}{3} + \frac{2}{3} = \frac{1}{3}\)
Vậy x = \(\frac{1}{3}\)
b) Ta có: \(\frac{- 2}{5} + \frac{2}{3} x + \frac{1}{6} x = \frac{- 4}{15}\)
\(\Rightarrow \frac{- 2}{5} + x . \left(\right. \frac{2}{3} + \frac{1}{6} \left.\right) = \frac{- 4}{15}\)
\(\Rightarrow x . \frac{5}{6} = \frac{- 4}{15} - \frac{- 2}{15}\)
\(x . \frac{5}{6} = \frac{- 2}{15}\)
\(\Rightarrow x = \frac{- 2}{15} : \frac{5}{6} = \frac{- 4}{25}\)
Vậy x = \(\frac{- 4}{25}\)
c) Ta có: \(\frac{3}{2} x + \frac{- 2}{5} - \frac{2}{3} . x = \frac{- 4}{15}\)
\(\Rightarrow \frac{3}{2} x - \frac{2}{3} x + \frac{- 2}{5} = \frac{- 4}{15}\)
\(\Rightarrow x . \left(\right. \frac{3}{2} - \frac{2}{4} \left.\right) = \frac{- 4}{15} - \frac{- 2}{15}\)
\(\Rightarrow x . \frac{5}{6} = \frac{- 2}{15}\)
\(\Rightarrow x = \frac{- 2}{15} : \frac{5}{6} = \frac{- 4}{25}\)
Vậy x = \(\frac{- 4}{25}\)
24 tháng 5 2022
a: \(=\dfrac{-3}{7}+\dfrac{-9}{35}-\dfrac{2}{5}\)
\(=\dfrac{-15-9-14}{35}=\dfrac{-38}{35}\)
b: \(=\left(\dfrac{15}{24}-\dfrac{7}{12}\right)\cdot\dfrac{-12}{7}\)
\(=\dfrac{15-14}{24}\cdot\dfrac{-12}{7}=\dfrac{1}{24}\cdot\dfrac{-12}{7}=\dfrac{-1}{14}\)
c: \(=\dfrac{7}{5}\cdot\dfrac{15}{19}\cdot\dfrac{-8}{15}+\dfrac{7}{15}\)
\(=\dfrac{-56}{95}+\dfrac{7}{15}\)
\(=\dfrac{-7}{57}\)
6 tháng 3 2017
b, \(\dfrac{x-3}{4}=\dfrac{15}{20}\)
<=> \(\dfrac{x-3}{4}=\dfrac{3}{4}\)
=> x-3=3
<=> x=6
Vậy x=6
TT
9 tháng 6 2017
\(a,\dfrac{x}{15}=\dfrac{4}{y}=\dfrac{-2}{5}\)
* \(\dfrac{x}{15}=\dfrac{-2}{5}\)
\(\Rightarrow\dfrac{x}{15}=\dfrac{-6}{15}\)
\(\Rightarrow x=-6\)
*\(\dfrac{4}{y}=\dfrac{-2}{5}\)
\(\Rightarrow\dfrac{4}{y}=\dfrac{4}{-10}\)
\(\Rightarrow y=-10\)
Vậy x = - 6 ; y = - 10
\(b,\dfrac{x-3}{4}=\dfrac{15}{20}\)
=> ( x - 3 ) . 20 = 4. 15
=> 20x - 60 = 60
=> 20x = 60 + 60
=> 20x = 120
=> x = 120 : 20
=> x = 6
Vậy x = 6
\(c,\dfrac{-5}{9}+\dfrac{-8}{15}+\dfrac{22}{-9}+\dfrac{-7}{15}< x\le\dfrac{-1}{3}+\dfrac{-1}{4}+\dfrac{-5}{12}\)
\(\Rightarrow\dfrac{-5}{9}+\dfrac{-8}{15}+\dfrac{-22}{9}+\dfrac{-7}{15}< x\le\dfrac{-4}{12}+\dfrac{-3}{12}+\dfrac{-5}{12}\)
\(\Rightarrow\left(\dfrac{-5}{9}+\dfrac{-22}{9}\right)+\left(\dfrac{-8}{15}+\dfrac{-7}{15}\right)< x\le-1\)
\(\Rightarrow-3+\left(-1\right)< x\le-1\)
\(\Rightarrow-4< x\le-1\)
\(\Rightarrow x=-3;-2;-1\)
2 tháng 4 2019
a, \(x:3\frac{1}{15}=1\frac{1}{2}\)
\(\Rightarrow x=1\frac{1}{2}\cdot3\frac{1}{15}\)
\(\Rightarrow x=\frac{3}{2}\cdot\frac{46}{15}=\frac{3\cdot46}{2\cdot15}=\frac{1\cdot23}{1\cdot5}=\frac{23}{5}=4\frac{3}{5}\)
\(b)x\cdot\frac{15}{28}=\frac{3}{20}\)
\(\Rightarrow x=\frac{3}{20}:\frac{15}{28}=\frac{3}{20}\cdot\frac{28}{15}=\frac{1}{5}\cdot\frac{7}{5}=\frac{7}{25}\)
Tự làm nốt câu cuối :>
26 tháng 6 2022
a: \(A=\dfrac{-7}{28}\cdot\dfrac{15}{25}=\dfrac{-1}{4}\cdot\dfrac{3}{5}=\dfrac{-3}{20}\)
b: \(B=\dfrac{-5\cdot7}{14\cdot\left(-3\right)}=\dfrac{35}{42}=\dfrac{5}{6}\)
c: \(C=\dfrac{-1}{5}-\dfrac{1}{5}\cdot\dfrac{3}{5}=\dfrac{-1}{5}-\dfrac{3}{25}=\dfrac{-8}{25}\)
d: \(D=\dfrac{-3}{4}-\dfrac{1}{4}=-1\)
e: \(E=\dfrac{-4}{5}\left(1-\dfrac{15}{16}\right)=\dfrac{-4}{5}\cdot\dfrac{1}{16}=\dfrac{-1}{20}\)
f: \(F=\dfrac{6-7}{4}\cdot\dfrac{4+12}{22}=\dfrac{-1}{4}\cdot\dfrac{8}{11}=\dfrac{-2}{11}\)
NB
2
24 tháng 9 2016
(4510 x 520 ) / 7515=243
(0.8)5 / (0.4)6=0
215 x 94 / 66 x 83=9
0,4-2/5.(x+3/4)=15%
=0,4-0,4.(x+3/4)=0,15
=0,4.(x+3/4)=0,4-0,15=0,25
=(x+3/4)=0,25:0,4=5/8
=>x=5/8-3/4
=-1/8