You may want to review multiplying expressions with roots and conjugate polynomials first.
If the denominator has two terms, then it's harder. We can still get the radical out of the denominator, though, by using conjugates. For example, suppose we have to simplify (√7 + √2) / (√7 − √2). We multiply the numerator and denominator by the conjugate of the denominator. This is legal, because we can always multiply the numerator and denominator of a fraction by the same thing; usually, though, it's not very useful. Here, though, it is. Remember that the conjugate means you switch the sign in the middle between + and −. So in this case you multiply the numerator and denominator by √7 + √2. The numerator just becomes (√7 + √2)2 = 9 + 2√14, which isn't very interesting; but the denominator becomes (√7 + √2)(√7 − √2) = 7 − 2 = 5, which doesn't have any radical signs in it. This always happens, provided the denominator has two terms and the only roots are square roots. (It's more complicated with higher roots; we won't worry about that quite yet.) So the answer is 9 ⁄ 5 + 2 ⁄ 5 * √14.