Question

9х = х2-18. Помогите пж​

Answer 1

Ответ:

9х = х²-18

-x² + 9x + 18 = 0|×(-1)

x² - 9x - 18 = 0

D = b² - 4ac.

a = 1; b = -9; c = - 18

D = 81 - 4×(-18) = 81 + 72 = 153 > 0

x1,2 = (-b ± √D)/ 2a

x1,2 = (9 ± √153)/2

x1,2 = (9 ± 3√17)/2

x1 = (9 + 3√17)/2

x2 = (9 - 3√17)/2