初一的计算题.拜托,谢谢!

来源:百度知道 编辑:UC知道 时间:2024/05/25 08:27:47
(1) (2x-3y)^2 *(2x+3y)^2=
(2) (2a+3b-1)(-2a+3b+1)=
上次采纳的 我不是他舅 ,没有采纳964236,这次应该什么呢?

(1) (2x-3y)^2 *(2x+3y)^2
=[(2x-3y) *(2x+3y)]^2
=(4x^2-9y^2)
=16x^4-72x^2y^2+81y^4

(2) (2a+3b-1)(-2a+3b+1)
=[3b+(2a-1)][(3b-(2a-1)]
=9b^2-(2a-1)^2
=9b^2-4a^2+4a-1

1. [(2x-3y)*(2x+3y)]^2=(4x^2-9y^2)^2=16x^4-72x^2y^2+81y^4
2.[(3b+2a-1)*(3b-2a+1)]^2
=[9b^2-(2a-1)^2]^2
展开就是了

(1) (2x-3y)^2 *(2x+3y)^2
=[(2x-3y)(2x+3y)]^2
=(4x^2-9y^2)^2
=16x^4-72x^2y^2+81y^4;

(2) (2a+3b-1)(-2a+3b+1)
=[3b+(2a-1)][3b-(2a-1)]
=(3b)^2-(2a-1)^2
=9b^2-(4a^2-4a+1)
=9b^2-4a^2+4a-1.