Question

算数题2道1.（2a+3b-c)*(2a-3b+c) 2.(2m-3n)平方*（2m+3n）平方

Answer 1

（2a+3b-c)*(2a-3b+c)

=[2a+(3b-c)][2a-(3b-c)]

=4a^2-(3b-c)^2

=4a^2-(9b^2+c^2-6bc)

=4a^2-9b^2-c^2+6bc

(2m-3n)平方*（2m+3n）平方

=[(2m-3n)(2m+3n)]^2

=(4m^2-9n^2)^2

=16m^4+81n^4-72m^2*n^2

注意：^表示次方.