1题（m-n-3）² = 2题（a²+9)²-(a+3)(a-3)(a²+9)= 3题(a-2)[(a-2)²+6a]+(a+3)[(a+3)

题目

1题（m-n-3）² = 2题（a²+9)²-(a+3)(a-3)(a²+9)= 3题(a-2)[(a-2)²+6a]+(a+3)[(a+3)²-9a]= 4题 (x+y)²-4(x+y)(x-y)+4(x-y)²= 5题 先化简再求值[(x-y)²=(x+y)(x-y)]÷2x 其中x=3 y=-1.5

答案

原式=m²+n²+9+2mn+6m-6n原式=（a²+9）²-(a²-9)(a²+9)              =(a²+9)(a²+9-a²+9)&nbs...