
Domain restrictions are what x values make the denominator zero.
a² + 5a - 36 = (a + 9)(a - 4)
a ≠ -9 ; a ≠ 4
You find the GCF of 250 and 363 by factoring. 250 = 5^4 * 2. 363 = 3 * 11^2, and they have no common factors, so 250/363 is already in its simplest form!