亲,帮我解几道数学题哦、、

1-m-n+mn=(1-m)-n(1-m)=(1-m)(1-n) 4x^2+3z-3xz-4x=4x²-3xz-4x+3z=x(4x-3z)-(4x-3z) x^3y+3x-3x^2y^2-6y=x³y-3x²y²+3x-6y= 这个有问题 6ax+15b^2y^2=3(ax+5b²y²) 4a^2-b^2+6a-3b=(2a+b)(2a-b)+3(2a-b)=(2a-b)(2a+b-3) 9m^2+6mn-3m-n+n^2=9m²+6mn+n²-3m-n=(3m+n)²-(3m+n)=(3m+n)(3m+n-1) 4x^2-y^2+2x-y=(2x+y)(2x-y)+(2x-y)=(2x-y)(2x+y+1) a^3-b^3-a+b=(a-b)(a²+ab+b²)-(a-b)=(a-b)(a²+ab+b²-1） x^4y+2x^3y^2-x^2y-2xy^2=x³y(x+2y)-xy(x+2y)=xy(x+2y)(x²-1)=xy(x+2y)(x+1)(x-1)