1. \(\frac{4}{5}\cdot x=\frac{4}{7}\Rightarrow x=\frac{4}{7}:\frac{4}{5}=\frac{20}{28}=\frac{5}{7}\)
Vậy \(x=\frac{5}{7}\)
2.\(8x=7,8x+25\Rightarrow8x=\frac{39}{5}x+25=1000\)
\(1000:8=125\)và \(\left(1000-25\right):\frac{39}{5}=125\)
\(\Rightarrow x=125\)