Question

数学计算题：分解因式1.a²x²+16ax+642.25(x+y)²-16(x-y)²3.x²-6x+9-y²4.(a²

Answer 1

^2表示平方、

1.原式=(ax+8)^2

2.=(5x+5y-4x+4y)(5x+5y+4x-4y)

=(x+9y)(9x+y)

3.=(x-3)^2-y^2

=(x-y-3)(x+y-3)

4.=(a^2+b^2-1+2ab)(a^2+b^2-1-2ab)

=[(a+b)^2-1][(a-b)^2-1]

=(a+b+1)(a+b-1)(a-b+1)(a-b-1)

5.∠BPC=130°

6.= =哪里来的D?

有图没有?

没图的话、D有很多种情况的、