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

（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

解
(1)16x^4-72x²+81
=(4x²)²-2×4x×9+9²
=(4x²-9)²
=(2x-3)²(2x+3)²
(2)3(a^4+a²b²+b^4)-9a²b²
=3(a^4+b^4-2a²b²)

1. 16x^4-72x^2y^2+81y^4
   =(4x^2-9y^2)^2
   =(2x+3y)^2(2x-3y)^2