Answer
$\frac{x-6}{4}$
Work Step by Step
To simplify, divide both the numerator and denominator by their greatest common factor.
Use the the factorization to find the GCF.
$\frac{x^2-12x+36}{4x-24}=\frac{(x-6)(x-6)}{4(x-6)}=\frac{(x-6)(x-6)\div(x-6)}{4(x-6)\div(x-6)}=\frac{x-6}{4}$