Lời giải:

\(1\frac{1}{3}:0,8=\frac{2}{3}:(0,1x)\)

\(\frac{4}{3}:\frac{8}{10}=\frac{2}{3}:\frac{x}{10}\)

\(\frac{5}{3}=\frac{2}{3}:\frac{x}{10}\)

\(\frac{x}{10}=\frac{2}{3}:\frac{5}{3}=\frac{2}{5}\)

\(x=\frac{2}{5}.10=4\)

\(1\frac{1}{3}:0,8=\frac{2}{3}:\left(0,1x\right)\)

\(\frac{4}{3}:\frac{8}{10}=\frac{2}{3}.\frac{10}{x}\)

\(\frac{4}{3}.\frac{5}{4}=\frac{20}{3x}\)

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

\(\frac{1}{x}=\frac{5}{3}.\frac{3}{20}\)

\(\frac{1}{x}=\frac{1}{4}\)

\(x=4\)

Tìm x trong các tỉ lệ thức sau :

\(\left(a\right)3,8\div\left(2x\right)=\frac{1}{4}\div2\frac{2}{3}\)

\(3,8\div\left(2x\right)=\frac{3}{32}\)

\(2x=3,8\div\frac{3}{32}\)

\(2x=40\frac{8}{15}\)

\(x=20\frac{4}{15}\)

\(\left(0,25x\right)\div3=\frac{5}{6}\div0,125\)

\(\left(0,25x\right)\div3=6\frac{2}{3}\)

\(\left(0,25x\right)=6\frac{2}{5}\times3\)

\(\left(0,25x\right)=20\)

\(x=80\)

\(0,01\div2,5=\left(0,75x\right)\div0,75\)

\(0,004=\left(0,75x\right)\div0,75\)

\(0,75x=0,75\times0,004\)

\(0,75x=0,003\)

\(x=0,004\)

\(1\frac{1}{3}\div0,8=\frac{2}{3}\div\left(0,1x\right)\)

\(1\frac{2}{3}=\frac{2}{3}\div\left(0,1x\right)\)

\(\left(0,1x\right)=\frac{2}{3}\div1\frac{2}{3}\)

\(\left(0,1x\right)=\frac{2}{5}\)

\(x=4\)

Dung ko z

bạn ghi ra đi mk giải cho (kb để mk ns cho dễ hiểu)

\(\dfrac{2}{3}:0.1x=\dfrac{4}{3}:0.8=\dfrac{4}{3}:\dfrac{4}{5}=\dfrac{5}{3}\)

=>0,1x=2/3:5/3=2/5

=>x=1/10:2/5=1/10x5/2=5/20=1/4

\(\dfrac{4}{3}:0,8=\)\(\dfrac{2}{3}:0,1x\)

\(\dfrac{4}{3}:\dfrac{4}{5}=\dfrac{2}{3}\)\(:\dfrac{1}{10}x\)

\(\dfrac{4}{3}.\dfrac{5}{4}=\dfrac{2}{3}:\dfrac{x}{10}\)

\(\dfrac{5}{3}=\dfrac{2}{3}.\dfrac{10}{x}\)

⇒\(\dfrac{10}{x}=\dfrac{5}{3}:\dfrac{2}{3}\)\(=\dfrac{5}{3}.\dfrac{3}{2}\)\(=\dfrac{5}{2}\)

⇒\(\dfrac{10}{x}=\dfrac{5}{2}\)⇒\(x=10:\dfrac{5}{2}=10.\dfrac{2}{5}=\dfrac{20}{5}=4\)

c) \(x:\left(-2,14\right)=\left(-3,12\right):1,2\)

=> \(x:\left(-2,14\right)=-2,6\)

=> \(x=\left(-2,6\right).\left(-2,14\right)\)

=> \(x=5,564\)

Vậy \(x=5,564.\)

d) \(2\frac{2}{3}:x=2\frac{1}{2}:\left(-0,06\right)\)

=> \(\frac{8}{3}:x=\frac{25}{12}:\left(-\frac{3}{50}\right)\)

=> \(\frac{8}{3}:x=-\frac{625}{18}\)

=> \(x=\frac{8}{3}:\left(-\frac{625}{18}\right)\)

=> \(x=-\frac{48}{625}\)

Vậy \(x=-\frac{48}{625}.\)

Chúc bạn học tốt!

a ) \(\frac{-3}{7}+x=\frac{1}{3}\Rightarrow x=\frac{1}{3}-\frac{-3}{7}\Rightarrow x=\frac{16}{21}\)

b) \(\frac{3}{4}+\frac{1}{4}:x=\frac{2}{5}\Rightarrow\frac{1}{4}:x=\frac{2}{5}-\frac{3}{4}\Rightarrow\frac{1}{4}:x=-\frac{7}{20}\Rightarrow x=\frac{1}{4}:\left(-\frac{7}{20}\right)=-\frac{5}{7}\)

c) \(1\frac{1}{3}:0,8=\frac{2}{3}:0,1x\Rightarrow\frac{2}{3}:0,1x=\frac{5}{3}\Rightarrow0,1x=\frac{2}{5}\Rightarrow x=4\)

d) \(\left|x-3\right|=\frac{1}{2}\Rightarrow\orbr{\begin{cases}x-3=\frac{1}{2}\\x-3=-\frac{1}{2}\end{cases}\Rightarrow\orbr{\begin{cases}x=\frac{7}{2}\\x=\frac{5}{2}\end{cases}}}\)

e) \(1\frac{1}{2}.x-4=0,5\Rightarrow\frac{3}{2}x=4,5\Rightarrow x=3\)

g) \(2^{x-1}=16\Rightarrow2^{x-1}=2^4\Rightarrow x-1=4\Rightarrow x=5\)

h) \(\left(x-1\right)^2=25\Rightarrow\orbr{\begin{cases}x-1=5\\x-1=-5\end{cases}\Rightarrow\orbr{\begin{cases}x=6\\x=-4\end{cases}}}\)

i) \(\left|2x-1\right|=5\Rightarrow\orbr{\begin{cases}2x-1=5\\2x-1=-5\end{cases}\Rightarrow\orbr{\begin{cases}x=3\\x=-2\end{cases}}}\)

k) \(0,2-\left|4,2-2x\right|=0\Rightarrow\left|4,2-2x\right|=0,2\Rightarrow\orbr{\begin{cases}4,2-2x=0,2\\4,2-2x=-0,2\end{cases}\Rightarrow\orbr{\begin{cases}x=2\\x=2,2\end{cases}}}\)