Răspuns :
[tex] \it 0,7x - (1,5x - 0,7x + 0,2x) + 1,3x = \\ \\ \it \frac{7}{10} x - ( \frac{15}{10} x - \frac{7}{10} x + \frac{2}{10} x) + \frac{13}{10} x = \\ \\ \it \frac{7}{10}x - ( \frac{8}{10} + \frac{2}{10} x) + \frac{13}{10} x = \\ \\ \it \frac{7}{10} x - \frac{10}{10} x + \frac{13}{10} x = \\ \\ \it - \frac{3}{10} x + \frac{13}{10} x = \frac{10}{10}x = \boxed{x}[/tex]