约分:3x3?9x4=-13x-13x,a2?4a+42?a=______

约分:3x3?9x4=-13x-13x,a2?4a+42?a=______.
2024-11-19 18:41:10
推荐回答(1个)
回答1:

3x3
?9x4
=-
1
3x

a2?4a+4
2?a
=
(2?a)2
2?a
=2?a