Ответ: 1) -1,2

[tex]6.8 - \frac{1}{3} x = 7.2 \\ \frac{1}{3} x = 6.8-7.2 \\ \frac{1}{3} x = -0.4 \\ x = - \frac{2}{5} \div \frac{1}{3} \\ x = - \frac{6}{5} \\ x =- 1 \frac{1}{5} \\ x =- 1.2[/tex]