①原式=[(4x²+6x+9)(2x+3)(2x-3)]/(2x+3)=(4x²+6x+9)(2x-3)=8x³-27 [代数式的运算]
②原式=(a^n-1)² 原式=(a-2)a^n
③原式=(5x²-13y²)²-[4(x²-3y²)]²=(5x²-13y²+4x²-12y²)(5x²-13y²-4x²+12y²)=(9x²-25y²)(x²-y²)
=(3x+5y)(3x-5y)(x+y)(x-y)