算数题2道

（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。

.（2a+3b-c)*(2a-3b+c)
=[2a+(3b-c)]*[2a-(3b-c)]
=4a²-（3b-c）²

.(2m-3n)平方*（2m+3n）平方
=【（2m-3n）（2m+3n）】²
=（4m²-9n²）²

这两道就是平方差的运算 第二题还要幂函数
1.（2a+3b-c）*(2a-(3b-c))
=(2a)^2-(3b-c)^2
=4a^2-9b^2-c^2+6bc

2.(2m-3n)^2*(2m+3n)^2
=[(2m-3n)(2m+3n)]^2
=(4m^2-9n^2)^2
=16m^4+81n^4-72m^2n^2 我没抄。。想不到一样

1.原式=[2a+(3b-c)][2a-(3b-c)]=4a^2-(3b-c)^2=4a^2-9b^2+6bc-c^2
2.原式=[(2m-3n)(2m+3n)]^2=(4m^2-9n^2)^2=16m^4-72m^2*n^2+81n^4