(1)16x的4次方-72x²+81(2)3(a的4次方+a²b²+b的4次方)-9a&s
3个回答

(1)16x的4次方-72x²+81

=(16x²-9)²

=(4x+3)²(4x-3)²

(2)3(a的4次方+a²b²+b的4次方)-9a²b²

=3a的4次方-6a²b²+3b的4次方

=3(a的4次方-2a²b²+b的4次方)

=3(a²-b²)²

=3(a+b)²(a-b)²

(3)24a²b²-6(a²+b²)²

=6[4a²b²-(a²+b²)²]

=6(2ab-a²-b²)(2ab+a²+b²)

=-6(a-b)²(a+b)²

(4)9(x-1)²-6(x²-1)y+y²

=(x-1)²(9-6y+y²)

=(x-1)²(y-3)²

(5)2(a²+b²)(a+b)²-(a²-b²)²

=2(a²+b²)(a+b)²-(a+b)²(a-b)²

=(a+b)²[2(a²+b²)-(a-b)²]

=(a+b)²[a²+b²+2ab]

=(a+b)²(a+b)²

=(a+b)的4次方