\(2\frac{1}{5}+\frac{3}{5}x=\frac{3}{4}\)
\(\Rightarrow\frac{11}{5}+\frac{3}{5}x=\frac{3}{4}\Rightarrow\frac{3}{5}x=\frac{3}{4}-\frac{11}{5}=-\frac{29}{20}\Rightarrow x=-\frac{29}{20}:\frac{3}{5}=-\frac{29}{12}\)
Vậy x=-29/12
3/5x=3/4-21/5
3/5x=-69/20
69/115x=69/20
115x=20
x=20:115
x=4/23
3/5x=3/4-21/5
3/5x=-69/20
x=-69/20:3/5
x=-23/4
\(2\frac{1}{5}+\frac{3}{5}x=\frac{3}{4}\)
\(\frac{11}{5}+\frac{3}{5}x=\frac{3}{4}\)
\(\frac{3}{5}x=\frac{3}{4}-\frac{11}{5}\)
\(\frac{3}{5}x=\frac{15}{20}-\frac{44}{20}\)
\(\frac{3}{5}x=\frac{-29}{20}\)
\(x=\frac{-29}{20}:\frac{3}{5}\)
\(x=\frac{-29}{20}\)x\(\frac{5}{3}\)
\(x=\frac{-29x5}{20x3}\)
\(x=\frac{-29}{12}\)