(3a+1)(3a-1)+3(a+2)(a-2)-(7a+1)(a-1)重点(7a+1)(a-1)

来源:学生作业帮助网 编辑:六六作业网 时间:2024/12/20 18:23:07
(3a+1)(3a-1)+3(a+2)(a-2)-(7a+1)(a-1)重点(7a+1)(a-1)(3a+1)(3a-1)+3(a+2)(a-2)-(7a+1)(a-1)重点(7a+1)(a-1)(3

(3a+1)(3a-1)+3(a+2)(a-2)-(7a+1)(a-1)重点(7a+1)(a-1)
(3a+1)(3a-1)+3(a+2)(a-2)-(7a+1)(a-1)
重点(7a+1)(a-1)

(3a+1)(3a-1)+3(a+2)(a-2)-(7a+1)(a-1)重点(7a+1)(a-1)
(7a+1)(a-1)不能利用公式.
原式=9a^2-1+3a^2-12-7a^2+6a+1=5a^2+6a-12

=(3a+1)(3a-1)+3(a+2)(a-2)-(6a+a+1)(a-1)
=(3a+1)(3a-1)+3(a+2)(a-2)-(a+1)(a-1)-6a(a-1)
下面自己算了,应该乘乘,加加,减减就好了