3) (5/2x+6) - (1 / 6x^2-18x) = 29 / 27-3x^2.

Перепишем: 5/(2(x+3)) - 1/(6x(x-3)) = 29/(3(9-x^2)).

5/(2(x+3)) - 1/(6x(x-3)) = -29/(3(x^2-9)).

5/(2(x+3)) - 1/(6x(x-3)) = -29/(3(x-3)(x+3)).

Общий знаменатель 6x(x-3)(x+3).

5 * 3x(x-3) - 1 * (x+3) = -29 * 2x.

15x(x-3) - (x+3) = -58x.

15x^2 - 45x - x - 3 = -58x.

15x^2 - 46x - 3 = -58x.

15x^2 + 12x - 3 = 0.

5x^2 + 4x - 1 = 0.

D = 4^2 - 4(5)(-1) = 16 + 20 = 36.

x1 = (-4 + 6) / 10 = 2/10 = 1/5.

x2 = (-4 - 6) / 10 = -10/10 = -1.