77/45

7/6

29/10

\(\dfrac{3}{5}+\dfrac{4}{3}\times\dfrac{5}{6}=\dfrac{3}{5}+\dfrac{10}{9}=\dfrac{27}{45}+\dfrac{50}{45}=\dfrac{77}{45}\)

\(2-\dfrac{7}{6}+\dfrac{1}{3}=\dfrac{12}{6}-\dfrac{7}{6}+\dfrac{2}{6}=\dfrac{7}{6}\)

\(\dfrac{7}{6}\times3-\dfrac{3}{5}=\dfrac{7}{2}-\dfrac{3}{5}=\dfrac{35}{10}-\dfrac{6}{10}=\dfrac{29}{10}\)

Giải:

B=1,4 .15/49 - (4/5+2/3) :2 1/5

B=7/5.15/49 - 22/15 : 11/5

B=3/7 - 2/3

B=-5/21

Chúc bạn học tốt!

thanks nha! 

mình cũng chúc bạn học tốt

`1/8 = (1.5)/(8.5) = 5/40`

`1/5 = (1.8)/(5.8) = 8/40`

`5/40 < x/40 < 8/40`

`=> x = 6` và `7`

Vậy `1/8 < 6/40 ; 7/40 < 1/5`

1/8<x/40<1/5

5/40<x/40<8/40

=>5<x<8

=>x E (5,6,7)

Vậy x=(5,6,7)

giúp mình với

a. x + 3/10= 25/8

x = 25/8-3/10

x = 113/40

b. x/35 = 4/5-5/7

x/35 = 3/35

vậy x=3

a: \(x\ge1\frac15\)

=>\(x-1\frac15>0;x-\frac15>0\)

=>\(M=x-1\frac15+x-\frac15-3\frac15=2x-\frac65-\frac15-\frac{16}{5}=2x-\frac{23}{5}\)

b: \(x\le\frac15\)

=>\(x-\frac15\le0\)

=>\(x-\frac15-1\le-1<0\)

=>\(x-1\frac15<0\)

Ta có: \(M=\left|1\frac15-x\right|+\left|x-\frac15\right|-3\frac15\)

\(=\frac65-x+\frac15-x-\frac{16}{5}=\frac{-9}{5}-2x\)

c: \(\frac15

=>\(x-\frac15>0;x-\frac65<0\)

Ta có: \(M=\left|1\frac15-x\right|+\left|x-\frac15\right|-3\frac15\)

\(=\frac65-x+x-\frac15-3-\frac15=1-3-\frac15=-2-\frac15=-\frac{11}{5}\)

Quy đồng : \(\dfrac{20}{80}>x>\dfrac{16}{80}\)

Giá trị của x là : \(\dfrac{19}{80};\dfrac{18}{80};\dfrac{17}{80}\)

\(a,x-\dfrac{3}{4}=\dfrac{1}{7}\\ x=\dfrac{1}{7}+\dfrac{3}{4}\\ x=\dfrac{25}{28}\\ b,x+\dfrac{7}{5}=\dfrac{9}{8}.\dfrac{4}{27}\\ x+\dfrac{7}{5}=\dfrac{1}{6}\\ x=\dfrac{1}{6}-\dfrac{7}{5}\\ x=\dfrac{-37}{30}\\ c,\dfrac{2}{5}-\dfrac{3}{7}=\dfrac{x}{70}\\ \dfrac{-1}{35}=\dfrac{x}{70}\\ \dfrac{-2}{70}=\dfrac{x}{70}\\ x=-2\\ d,\dfrac{2}{9}-\dfrac{7}{8}.x=1\\ \dfrac{7}{8}.x=\dfrac{2}{9}-1\\ \dfrac{7}{8}.x=\dfrac{-7}{9}\\ x=\dfrac{-7}{9}:\dfrac{7}{8}\\ x=\dfrac{-8}{9}\)

\(a,x-\dfrac{3}{4}=\dfrac{1}{7}\)

\(\Rightarrow x=\dfrac{1}{7}+\dfrac{3}{4}\)

\(\Rightarrow x=\dfrac{25}{28}\)

\(b,x+\dfrac{7}{5}=\dfrac{9}{8}.\dfrac{4}{27}\)

\(\Rightarrow x+\dfrac{7}{5}=\dfrac{1}{6}\)

\(\Rightarrow x=\dfrac{1}{6}-\dfrac{7}{5}\)

\(\Rightarrow x=-\dfrac{37}{30}\)

\(c,\dfrac{2}{5}-\dfrac{3}{7}=\dfrac{x}{70}\)

\(\Rightarrow\dfrac{-1}{35}=\dfrac{x}{70}\)

\(\Rightarrow35x=-70\)

\(\Rightarrow x=-2\)

\(d,\dfrac{2}{9}-\dfrac{7}{8}.x=1\)

\(\Rightarrow\dfrac{7}{8}x=\dfrac{2}{9}-1\)

\(\Rightarrow\dfrac{7}{8}x=-\dfrac{7}{9}\)

\(\Rightarrow x=-\dfrac{8}{9}\)

Giúp mình vs ạ. Cần gấp

\(\dfrac{3}{4}\)+\(\dfrac{1}{4}\): x=\(\dfrac{-2}{5}\)

⇒\(\dfrac{1}{4}\):x=\(\dfrac{-2}{5}\)-\(\dfrac{3}{4}\)

⇒ x=\(\dfrac{1}{4}\): \(\dfrac{-23}{20}\)

⇒ x=\(\dfrac{-5}{23}\)

x:5/3=9/5+2/5

x:5/3=11/5

x=11/5.5/3

x=11/3

x : 5/3 = 9/5 - 2/5

x : 5/3 = 7/5

x = 7/5 x 5/3

x = 7/3