Bài 3:
a: x/5=2/3
nên x=2/3x5=10/3
b: \(\dfrac{x}{3}-\dfrac{1}{2}=\dfrac{1}{5}\)
\(\Leftrightarrow x\cdot\dfrac{1}{3}=\dfrac{7}{10}\)
hay x=21/10
c: \(\dfrac{x}{5}+\dfrac{1}{2}=\dfrac{6}{10}\)
nên \(\dfrac{x}{5}=\dfrac{6}{10}-\dfrac{1}{2}=\dfrac{1}{10}\)
hay x=1/2
g: \(\dfrac{x-12}{4}=\dfrac{1}{2}\)
nên x-12=2
hay x=14
h: x+4/5=2/3
=>x=2/3-4/5=10/15-12/15=-2/15