x平方+x+1+(1-x)分之x立方
=x平方+x+1+(1-x)分之(x立方-1)+(1-x)分之1
=x平方+x+1+(1-x)分之(x-1)(x平方+x+1)+(1-x)分之1
=x平方+x+1-(x平方+x+1)+(1-x)分之1
=(1-x)分之1
x平方+x+1+(1-x)分之x立方
=x平方+x+1+(1-x)分之(x立方-1)+(1-x)分之1
=x平方+x+1+(1-x)分之(x-1)(x平方+x+1)+(1-x)分之1
=x平方+x+1-(x平方+x+1)+(1-x)分之1
=(1-x)分之1