求完全平方公式和因式分解的计算题

(1)(x²+1)²-4x²
(2)(2x-y)²-2(2x-y)+1
(3)(x+y)²-2(x²-y²)+(x-y)²
(4)（a+1）(a+5)+4
(5)（m²+n²）²-4m²n²
(6) x²+2x+1-y²
(7) -4x^2+12xy-9y^2
(8) 9(2a-b)^2-6(2a-b)+1
(9) -2m^3+24m^2-72m
(10) -x^4+2x^2y^2-y^4
(11) (x+y)^2+4(x-y)^2-4(x^2-y^2)
(12) (a^2+1)^2-4a^2
(13) y^n+1 -3y^n +2y^n-1
(14) (x^2+3x+4)^2 +(x^2+3x+4)-6
(15) -(x-y)^3-4(x-y)^2+12(x-y)