Let $\displaystyle f(x)=\frac{5}{x- 3}$. Then according to the definition of derivative

$\displaystyle f'(x) = \lim_{t\to x}$
(Your answer above and the next few answers below will involve the variables $t$ and $x$.)

NOTE: In this question, webwork will only grade an answer once you have entered BOTH the numerator and the denominator. Until then, it will mark answers as wrong.
The expression inside the limit simplifies to a simple fraction with:

Numerator $=$

Denominator $=$

We can cancel the factor appearing in the denominator against a similar factor appearing in the numerator leaving a simpler fraction with:

Numerator $=$

Denominator $=$

Taking the limit of this fractional expression gives us
$f'(x) =$
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