( 2x^2 +x/x^3 -1 - x+1/x^2 +x+1)×(1+x+1/x - x+5/x+1)
(2x²+x/x³-1-x+1/x²+x+1)(1+x+1/x-x+5/x+1)= 4(x+3)(x^4+1)/x³