分母=（X-1）^2
分子=X^3*(X^2-1)-5*X^3+7*X^2-7*X+3
=X^3*(X^2-1)-5*X^2*(X-1)+2*X^2-7*X+3
=X^3*(X^2-1)-5*X^2*(X-1)+2*X*(X-1)-5*X+3
=X^3*(X^2-1)-5*X^2*(X-1)+2*X*(X-1)-5*(X-1)-2
原式=[X^3*(X+1)-5*X^2-2*X-5]/(X-1)-2/(X-1)^2
左式分子=X^4+X^3-5*X^2-2*X-5
=>X^3*（X-1）+2*X^2*(X-1)-3*X*(X-1)-5(X-1)-10
=>左式=X^3+2*X^2-3*X-5-10/(X-1)=X^2*(X-1)+3*X*(X-1)-5-10/(X-1)
原式=X^2*(X-1)+3*X*(X-1)-5-10/(X-1))-2/(X-1)^2
就化简到这吧,累死我了!