Очень срочно
(x^3+4x^2+2x-1):(x+1)

(x^3+4x^2+2x-1):(x+1) \frac{3х+8х+2х-1}{х+1}  \frac{13х-1}{х+1} 

(x³+4x²+2x-1)/(x+1)=(x³+2x²+x+2x²+x-1)/(x+1)=(x*(x²+2x+1)+(2x²+x-1))/(x+1)==(x*(x+1)²+2*(x+1)*(x-0,5))/(x+1)=(x+1)*(x*(x+1)+2x-1)/(x+1)=x²+3x-1.