Question

Tìm x biết:
a)\(\frac{5}{9}:x=\frac{7}{4}:\frac{3}{10}\)                                         b)\(\frac{3.x-7}{8}=\frac{5}{2}\)

Answer 1

a) \(\frac{5}{9}:x=\frac{7}{4}:\frac{3}{10}\)

\(\frac{5}{9}:x=\frac{35}{6}\)

\(x=\frac{5}{9}:\frac{35}{6}\)

\(x=\frac{2}{21}\)

Vậy \(x=\frac{2}{21}\)

b) \(\frac{3.x-7}{8}=\frac{5}{2}\)

\(\left(3.x-7\right).2=5.8\)

\(2\left(3.x-7\right)=40\)

\(6.x-14=40\)

\(6.x=40+14\)

\(6.x=54\)

\(x=54:6\)

\(x=9\)

Vậy \(x=9\)

Answer 2

 

a)59:x=74:310

\(\frac{5}{9}:x=\frac{35}{6}\)

\(x=\frac{5}{9}:\frac{35}{6}\)

 \(x=\frac{2}{21}\)

b, \(\frac{3x-7}{8}=\frac{5}{2}\)

\(=>\left(3x-7\right)\cdot2=5\cdot8\)

\(\left(3x-7\right)\cdot2=40\)

\(3x-7=40:2\)

\(3x-7=20\)

\(3x=20+7\)

\(3x=27\)

\(x=27:3\)

\(x=9\)