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(3m-2n) (4n-5m)怎么算?

题目详情
(3m-2n) (4n-5m)怎么算?
▼优质解答
答案和解析
(a^2+a+1) (a^2-a+1),=[(a^2+1)+a] [(a^2+1)-a] = (a^2+1)^2-a ^2 = a^4+2a^2+1-a ^2= a^4+a^2+1
(2X-3Y) (2X+3Y) (4X^2+9Y^2)=(4X^2-9Y^2)(4X^2+9Y^2)=16X^4-81Y^4