Answer
$\frac{x-4}{3}$, $x\ne4$
Work Step by Step
We must factor the top and bottom separately. First, we factor the top as $(x-4)(x-4)$. Then, we pull out 3 on the bottom, which gives us $3(x-4)$. This gives us the following fraction:
$\frac{(x-4)(x-4)}{3(x-4)}$
Then, we are allowed to cancel out the $x - 4$ factors.
This leads us to an answer of $\frac{x-4}{3}$. Even though there is no longer an $x - 4$ factor in the denominator, we must still declare that $x\ne 4$ because $x - 4$ was still initially in the bottom of the fraction.
