Question 1099954
I think you mean difference quotient,
{{{(f(x+h)-f(x))/h}}}
In this case,
{{{f(x+h)=9(x+h)+6=9x+9h+6}}}
So,
{{{(f(x+h)-f(x))/h=(9x+9h+6-9x-6)/h}}}
{{{(f(x+h)-f(x))/h=(9h)/h}}}
{{{(f(x+h)-f(x))/h=9}}}