Пошаговое объяснение:

[tex]9 {x}^{2} - 2x - 7 = 0 | \div 9 \\ {x}^{2} - \frac{2}{9}x - \frac{7}{9} = 0 \\ x1x2 = - \frac{7}{9} \\ x1 + x2 = \frac{2}{9} \\ \\ x1 = 1 \\ x2 = - \frac{7}{9} [/tex]