The document provides instruction on factoring perfect square trinomials. It defines a perfect square trinomial as having the form x^2 + 2xy + y^2, where the first term is a perfect square, the middle term is twice the product of the first and last terms, and the last term is a perfect square. Examples are provided of determining if an expression is a perfect square trinomial and factoring perfect square trinomials into the form (x + y)^2 or (x - y)^2. The process of factoring other trinomials by factoring out the greatest common factor is also demonstrated.