Question 256026
Do you mean {{{x^2-4/x^2-5x+6}}} which is x^2-4/x^2-5x+6
or 
{{{ (x^2-4)/(x^2-5x+6)}}} which is (x^2-4)/(x^2-5x+6)


Assuming you forgot to put the very important parentheses and the square sign ^ which is found above the 6:

{{{ (x^2-4)/(x^2-5x+6)}}}=
(x-2)(x+2)/(x-3)(x-2)=
(x+2)/(x-3)