1. ## Difference quotient

$f\left(x \right)={x}^{3}+x,\frac{f\left(x+h \right)-f\left(x \right)}{h},h\neq0$

Thanks

2. Originally Posted by Amy
$f\left(x \right)={x}^{3}+x$
Then $f(x + h) = (x + h)^3 + (x + h).$

Now substitute and work with it, what do you get?

3. Originally Posted by Amy
$f\left(x \right)={x}^{3}+x,\frac{f\left(x+h \right)-f\left(x \right)}{h},h\neq0$
$\frac{(x+h)^3+x+h-x^3-x}{h}=???$