Question 1185178
<pre>
{{{(x^2-16)/(x^2-7x+12)}}}

Factor the numerator as (x-4)(x+4)
Factor the denominator as (x-4)(x-3)

{{{((x-4)(x+4))/((x-4)(x-3))}}}

Cancel the (x-4)'s

{{{((cross(x-4))(x+4))/((cross(x-4))(x-3))}}}

{{{(x+4)/(x-3)}}}

Edwin</pre>