a) x = $\frac{3}{4}$ + $\frac{1}{-12}$ = $\frac{2}{3}$ b) x + $\frac{3}{5}$ = $\frac{1}{15}$ x = $\frac{1}{15}$ - $\frac{3}{5}$ x = $\frac{-8}{15}$ c) $\frac{-1}{2}$ - x = $\frac{1}{3}$ + $\frac{-1}{4}$ $\frac{-1}{2}$ - x = $\frac{1}{12}$ x = $\frac{-1}{2}$ - $\frac{1}{12}$ x = $\frac{-7}{12}$ Chúc cậu học tốt!
