Question 689925
{{{(x^2-5x+6)/(x^2-4x)}}}

first factor completely numerator {{{(x^2-5x+6)}}} 

*[invoke factoring_quadratics 1, -5, 6]

and we can factor denominator and write it as {{{x(x-4)}}}


now we have {{{((x-2)(x-3))/x(x-4)}}}...this is all we can do and you can see there are no common factors in nominator and denominator to be canceled, and this is the simplest way to write your expression