Question

Answer 1

\(8\dfrac{1}{3}:11\dfrac{2}{3}=13:2x\)

\(\Rightarrow\dfrac{25}{3}:\dfrac{35}{3}=13:2x\)

\(\Rightarrow\dfrac{5}{7}=13:2x\)

\(\Rightarrow2x=13:\dfrac{5}{7}\)

\(\Rightarrow2x=\dfrac{91}{5}\)

\(\Rightarrow x=\dfrac{91}{5}:2\)

\(\Rightarrow x=\dfrac{91}{10}\)

Answer 2

\(\left(x-1\right):24,5=5:8,75\)

\(\Rightarrow8,75\cdot\left(x-1\right)=24,5\cdot5\)

\(\Rightarrow8,75\cdot\left(x-1\right)=122,5\)

\(\Rightarrow x-1=14\)

\(\Rightarrow x=14+1\)

\(\Rightarrow x=15\)

Answer 3

\(\dfrac{x}{18}=\dfrac{-3}{3,6}\)

\(\Rightarrow3,6x=-3\cdot18\)

\(\Rightarrow3,6x=-54\)

\(\Rightarrow x=\dfrac{-54}{3,6}\)

\(\Rightarrow x=-15\)

Answer 4

 \(2,5:7,5=x:3,5\)

\(\Rightarrow7,5x=2,5\cdot3,5\)

\(\Rightarrow7,5x=8,75\)

\(\Rightarrow x=\dfrac{8,75}{7,5}\)

\(\Rightarrow x=\dfrac{7}{6}\)

Answer 5

\(3\dfrac{4}{5}:2x=0,25:2\dfrac{2}{3}\)

\(\Rightarrow\dfrac{19}{5}:2x=0,25:\dfrac{8}{3}\)

\(\Rightarrow\dfrac{19}{5}:2x=\dfrac{3}{32}\)

\(\Rightarrow2x=\dfrac{19}{5}:\dfrac{3}{32}\)

\(\Rightarrow2x=\dfrac{608}{15}\)

\(\Rightarrow x=\dfrac{304}{15}\)

Answer 6

\(2\dfrac{1}{2}:0,01=0,75:\dfrac{3}{4}x\)

\(\Rightarrow2\dfrac{1}{2}\cdot\dfrac{3}{4}x=0,01\cdot0,75\)

\(\Rightarrow\dfrac{15}{8}x=0,0075\)

\(\Rightarrow x=0,0075:\dfrac{15}{8}\)

\(\Rightarrow x=0,004\)

Answer 7

\(\dfrac{72-x}{3}=\dfrac{x-18}{5}\)

\(\Rightarrow5\cdot\left(72-x\right)=3\cdot\left(x-18\right)\)

\(\Rightarrow360-5\cdot x=3\cdot x-54\)

\(\Rightarrow3\cdot x+5\cdot x=360+54\)

\(\Rightarrow8\cdot x=414\)

\(\Rightarrow x=\dfrac{207}{4}\)

Answer 8

\(0,3:x=x:2,7\)

\(\Rightarrow x\cdot x=0,3\cdot2,7\)

\(\Rightarrow x^2=0,81\)

\(\Rightarrow x^2=0,9^2\)

\(\Rightarrow\left[{}\begin{matrix}x=0,9\\x=-0,9\end{matrix}\right.\)