[tex] \frac{1}{5} (x + 7) = \frac{2}{25} x + 10 \\ \frac{1}{5} x + \frac{7}{5} = \frac{2}{25} x + 10 \\ \frac{1}{5} x - \frac{2}{25} x = 10 - \frac{7}{5} \\ \frac{5}{25} x - \frac{2}{25} x = 10 - 1 \frac{2}{5} \\ \frac{3}{25}x = 8 \frac{3}{5} \\ x = \frac{43}{5} \div \frac{3}{25} = \frac{43}{5} \times \frac{25}{3} = \frac{43}{1} \times \frac{5}{3} = \frac{215}{3} = \\ = 71 \frac{2}{3} [/tex]
Myślę że pomogłem ;)