(-3a^n-1 b^n+1)*(-2ab)*(-a^2b)/a^n b^n

问题描述:

(-3a^n-1 b^n+1)*(-2ab)*(-a^2b)/a^n b^n
(x+3/x^2-3x - x-3/x^2-6x+9)/ x/x-3

(-3a^n-1 b^n+1)*(-2ab)*(-a^2b)/a^n b^n=-(6a^(n+2)b^(n+3)/a^nb^n=-6a^2b^3(x+3/x^2-3x - x-3/x^2-6x+9)/ x/x-3 =[(x+3)/x(x-3)-(x-3)/(x-3)^2]*(x-3)/x=(x+3)/x^2-1/x=3/x^2