[tex]W(1)=a*1^3+b*1^2+1+1=a+b+2\\W(-1)=a*(-1)^3+b*(-1)^2-1+1=-a+b\\\left \{ {{a+b+2=-5} \atop {-a+b=-9}} \right. \\\left \{ {{a+b=-7} \atop {-a+b=-9}} \right|+\\\left \{ {{2b=-16\ |:2} \atop {-a+b=-9}} \right.\\\left \{ {{b=-8} \atop {-a-8=-9}} \right.\\\left \{ {{b=-8} \atop {-a=-1}\ |:(-1)} \right.\\\left \{ {{b=-8} \atop {a=1} \right.\\W(x)=x^3-8x^2+x+1[/tex]
