Question

9（a－b）²+12（a²－b²）+4（a+b）²因式分解的结果

Answer 1

[3(a-b)+2(a+b)]^2=(5a-b)^2

答案是AAAAAAAAAAAAA

Answer 2

9（a－b）²+12（a²－b²）+4（a+b）²
=[3(a-b)+2(a+b)]²
=(3a-3b+2a+2b)²
=(5a-b)²

选A

追问

第七题呢？

追答

(y+1)²-(y²-1)
=(y+1)²-(y+1)(y-1)
=(y+1)[y+1-(y-1)]
=2(y+1)

选C