Question

Tìm x biết

a) \(\left(3,5x-25\right):\frac{3}{4}=60\)

b) \(-1\frac{1}{2}x+\frac{1}{5}=2\frac{3}{10}\)

Answer 1

a) \(3,5x-25=60.\frac{3}{4}\Leftrightarrow3,5x-25=45\)

\(\Leftrightarrow3,5x=45+25\Leftrightarrow3,5x=70\Leftrightarrow x=\frac{70}{3,5}=20\)

b) \(-1\frac{1}{2}x+\frac{1}{5}=2\frac{3}{10}\Leftrightarrow\frac{-3}{2}x=\frac{23}{10}\Leftrightarrow x=\frac{23}{10}:\frac{-3}{2}=\frac{-23}{15}\)

Answer 2

a)\(3,5x-25=60:\frac{3}{4}=80\)

\(3,5x=80+25\)

\(3,5x=105\)

\(x=105:3,5\)

\(x=30\)

b) \(\frac{-3}{2}x+\frac{1}{5}=\frac{23}{10}\)

\(\frac{-3}{2}x=\frac{23}{10}-\frac{1}{5}=\frac{21}{10}\)

\(x=\frac{21}{10}:\frac{-3}{2}\)

\(x=\frac{-7}{5}\)