[12(x+y)³(y-x)]³÷[4(x+y)²（x-y)]²=【12×12×12÷(4×4)(x+y)^9 (y-x)^3】 ÷【(x+y)^4 (x-y)^2】=【12×12×12÷(4×4)(x+y)^9 (y-x)^3】 ÷【(x+y)^4 (y-x)^2】=108(x+y)^5 (y-x)