1.15x^2n+7x^ny^n+1-4y^2n+2
问题描述：
1.15x^2n+7x^ny^n+1-4y^2n+2
2.(x^2+3x)^2-22(x^2+3x)+72
3.4x^4y^2-5x^2 y^2-9y^2
答
1.15x^2n+7x^ny^n+1-4y^2n+2 =[3x^n-y^(n+1)][5x^n+4y^(n+1)]2.(x^2+3x)^2-22(x^2+3x)+72 =(x^2+3x-4)(x^2+3x-18)=(x-1)(x+4)(x+6)(x-3)3.4x^4y^2-5x^2 y^2-9y^4 =(4x^2-9y^2)(x^2+y^2)=(2x+3y)(2x-3y)(x^2+y^2)