Answer 1

c) Ta có: \(\dfrac{x}{3}-\dfrac{1}{4}=\dfrac{-5}{6}\)

\(\Leftrightarrow x\cdot\dfrac{1}{3}=\dfrac{-5}{6}+\dfrac{1}{4}=\dfrac{-10}{12}+\dfrac{3}{12}=\dfrac{-7}{12}\)

hay \(x=\dfrac{-7}{12}:\dfrac{1}{3}=\dfrac{-7}{4}\)

d) Ta có: \(\dfrac{x+3}{15}=\dfrac{1}{3}\)

nên x+3=5

hay x=2

m) Ta có: \(0.25x-\dfrac{27}{8}x=\dfrac{3}{4}\)

\(\Leftrightarrow x\cdot\dfrac{-25}{8}=\dfrac{3}{4}\)

hay \(x=\dfrac{3}{4}:\dfrac{-25}{8}=\dfrac{3}{4}\cdot\dfrac{8}{-25}=\dfrac{-6}{25}\)