Пошаговое объяснение:
(x+3)/(x²+9) ·((x+3)/(x-3) +(x-3)/(x+3))=(x+3)/(x²+9) ·((x+3)²-(x-3)²)/((x-3)(x+3))=(x+3-x+3)(x+3+x-3)/((x²+9)(x-3))=6·2x/(x³-3x²+9x-27)=12x/(x³-3x²+9x-27)
