Question 1086904
{{{f(x)=2x^2+x+1}}}
{{{f(x+h)=2(x+h)^2+(x+h)+1=2(x^2+2hx+h^2)+x+h+1=2x^2+(4h+1)x+(2h^2+h+1)}}}
{{{f(x+h)-f(x)=2x^2+(4h+1)x+(2h^2+h+1)-2x^2-x-1=4hx+(2h^2+h)}}}
So,
{{{(f(x+h)-f(x))/h=4x+(2h+1)}}}