a, Ta có: x = 2,5 . 3/5 : 7,5 = 1/5

b, Ta có: x = 3 . 5 : 7 = 15/7

c, Ta có: x = -2 . 37 : 3,6 = -185/9

a) \(2.5\div7.5=x\div\frac{3}{5}\)

\(x\div\frac{3}{5}=\frac{1}{3}\)

\(x=\frac{1}{3}×\frac{3}{5}\)

\(x=\frac{3}{15}=\frac{1}{5}\)

Vậy, \(x=\frac{1}{5}\)

b) \(x\div5=3\div7\)

\(x\div5=\frac{3}{7}\)

\(x=\frac{3}{7}×5\)

\(x=\frac{15}{7}\)

Vậy, \(x=\frac{15}{7}\)

c) \(x\div37=\frac{-2}{3×6}\)

\(x\div37=\frac{-5}{9}\)

\(x=\frac{-5}{9}×37\)

\(x=\frac{-185}{9}\)

Vậy, \(x=\frac{-185}{9}\)

Cbht

a) x= 1/5

b) x = 0,01

a)2,5:7,5=x:3/5

0,(3)=x:3/5

\(\Rightarrow\)x= 1/5

b)x:2,5=0,003;0,75

x:2,5=1/250

\(\Rightarrow\)x=1/100

a) \(\left(\dfrac{1}{4}x\right):3=\dfrac{5}{6}:\dfrac{1}{8}\\ \left(\dfrac{1}{4}x\right):3=\dfrac{20}{3}\\ \dfrac{1}{4}x=\dfrac{20.3}{3}\\ \dfrac{1}{4}x=20\\ x=80\)

a: Ta có: \(\dfrac{0.25x}{3}=\dfrac{5.6}{0.125}\)

\(\Leftrightarrow x\cdot\dfrac{1}{4}=134.4\)

hay x=537,6

b: Ta có: \(\dfrac{2.5}{7.5}=x:\dfrac{3}{5}\)

\(\Leftrightarrow x:\dfrac{3}{5}=\dfrac{1}{3}\)

hay \(x=\dfrac{1}{5}\)

\(\dfrac{5}{2}:\dfrac{15}{2}=x:\dfrac{7}{5}\\ x:\dfrac{7}{5}=\dfrac{1}{3}\\ x=\dfrac{7}{15}\)

\(\begin{array}{l}a)\dfrac{x}{6} = \dfrac{{ - 3}}{4}\\x = \dfrac{{( - 3).6}}{4}\\x = \dfrac{{ - 9}}{2}\end{array}\)

Vậy \(x = \dfrac{{ - 9}}{2}\)

\(\begin{array}{l}b)\dfrac{5}{x} = \dfrac{{15}}{{ - 20}}\\x = \dfrac{{5.( - 20)}}{{15}}\\x = \dfrac{{ - 20}}{3}\end{array}\)

Vậy \(x = \dfrac{{ - 20}}{3}\)

a) \(2,5:7,5=x:\dfrac{3}{5}\)

\(\Rightarrow\dfrac{2,5}{7,5}=\dfrac{x}{\dfrac{3}{5}}\)

\(\Rightarrow x=\dfrac{\dfrac{3}{5}\cdot2.5}{7,5}\)

\(\Rightarrow x=\dfrac{1}{5}\) 

b) \(\dfrac{5}{6}:x=20:3\)

\(\Rightarrow\dfrac{\dfrac{5}{6}}{x}=\dfrac{20}{3}\)

\(\Rightarrow x=\dfrac{3\cdot\dfrac{5}{6}}{20}\)

\(\Rightarrow x=\dfrac{1}{8}\)

c) \(2\dfrac{2}{3}:x=1\dfrac{7}{9}\)

\(\Rightarrow\dfrac{8}{3}:x=\dfrac{16}{9}\)

\(\Rightarrow\dfrac{\dfrac{8}{3}}{x}=\dfrac{16}{9}\)

\(\Rightarrow x=\dfrac{\dfrac{8}{3}\cdot9}{16}\)

\(\Rightarrow x=\dfrac{3}{2}\)

a)

\(3\frac{4}{5}:40\frac{8}{15}=0,25:x\)

\(\Rightarrow\frac{19}{5}:\frac{608}{15}=\frac{1}{4}.x\)

\(\Rightarrow\frac{1}{4}.x=\frac{3}{32}\)

\(\Rightarrow x=\frac{3}{8}\)

Vậy x = 3 / 8

b) \(\frac{5}{6}:x=20:3\)

\(\Rightarrow\frac{5}{6x}=\frac{20}{3}\)

\(\Rightarrow120x=15\)

\(\Rightarrow x=\frac{1}{5}\)

Vậy x = 1 / 5

c)

\(x:2,5=0,003:0,75\)

\(\Rightarrow x.\frac{2}{5}=\frac{3}{1000}.\frac{4}{3}\)

\(\Rightarrow x.\frac{2}{5}=\frac{1}{250}\)

\(\Rightarrow x=\frac{1}{100}\)

d)

\(\frac{2}{3}:0,4=x:\frac{4}{5}\)

\(\Rightarrow\frac{2}{3}:\frac{2}{5}=\frac{5x}{4}\)

\(\Rightarrow\frac{5x}{4}=\frac{5}{3}\)

\(\Rightarrow15x=20\)

\(\Rightarrow x=\frac{4}{3}\)

Vậy x = 4 / 3

\(a,\dfrac{4}{x}=\dfrac{8}{x+1}\left(x\ne0;x\ne-1\right)\Rightarrow4x+4=8x\\ \Rightarrow x=1\\ b,\dfrac{x}{7}=\dfrac{x+16}{35}\Rightarrow35x=7x+112\\ \Rightarrow28x=112\Rightarrow x=4\\ c,\dfrac{6}{x-3}=\dfrac{7}{x-5}\left(x\ne3;x\ne5\right)\Rightarrow6x-30=7x-21\\ \Rightarrow x=-9\\ d,\dfrac{44-x}{3}=\dfrac{x-12}{5}\Rightarrow220-5x=3x-36\\ \Rightarrow8x=256\Rightarrow x=32\)