Question

умоляю срочно помогите 7х²-2х-9 = 0​

Answer 1

$7x {}^{2} - 2x - 9 = 0 \\ d = ( - 2) {}^{2} - 4 \times 7 \times ( - 9) = 4 + 254 = 256$

$x1 = \frac{2 + 16}{14} = \frac{9}{7} \\ x2 = \frac{2 - 16}{14} = - 1$

$x1 = \frac{9}{7} \\ x2 = - 1$

9/7 = 1 2/7