Tìm x / y biết a. 4 / 3 + x / y = 5 b. 3 / 4 x x / y

* Hướng dẫn giải

$$\begin{gathered} \mathrm{a}. \frac{4}{3}+\frac{x}{y}=5 \\ \frac{x}{y}=5-\frac{4}{3} \\ \frac{x}{y}=\frac{11}{3} \end{gathered}$$

$$\begin{gathered} \mathrm{b}. \frac{3}{4}\mathrm{x}\frac{x}{y}=\frac{6}{5} \\ \frac{x}{y}=\frac{6}{5}:\frac{3}{4} \\ \frac{x}{y}=\frac{8}{5} \end{gathered}$$