=(x²+3x+9)/(x-2)(x-2) * 3(x-2)/(x-3)(x²+3x+9) *(x-3)(x+3)=3(x+3)/(x-2)
x²+3x+9／x²-4x+4 × 3x-6／x³-27 × (x²-9) =x²+3x+9/(x-2)²×3(x-2)/(x-3)(x²+3x+9) × (x-3)(x+3)=3(x+3)/(x-2)
