x^2 - 9 = (7 + x)(x^2 - 5x + 6)
(x - 3)(x + 3) - (x + 7)(x - 2)(x - 3) = 0
(x - 3)(x + 3 - (x + 7)(x - 2) ) = 0
x1 = 3
x + 3 - (x^2 + 7x - 2x - 14) = 0
-x^2 - 4x + 17 = 0
D = 4^2 - 4(-1)*17 = 16 + 4*17 = 16 + 68 = 84 = 4*21
x2 = (4 - 2√21)/(-2) = -2 + √21
x3 = -2 - √21
ответ: x1 = 3; x2 = -2 + √21; x3 = -2 - √21
