Purple Math
Purplemath: Solving Polynomials: How To
Demonstrates the steps involved in solving a general polynomial, including how to use the Rational Roots Test and synthetic division. Points out when using a graphing calculator can be very helpful.
Purple Math
Purplemath: Special Factoring: Differences of Squares
Demonstrates how to use the formula for finding the differences of squares, and warns against trying to factor a sum of squares.
Windstream
Ojk's Precalculus Study Page: More Difficult Trig Equations
An introduction to solving trigonometric equations by using the reciprocal, negative, Pythagorean, and cofunction identities. Includes several examples and exercises with solutions at the bottom of the page.