Final answer:
The three types of equations are identities, contradictions, and equivalent equations. They differ based on their solution sets and truth values for variable inputs.
Step-by-step explanation:
There are three types of equations: identities, contradictions, and equivalent equations. An identity is an equation that is true for all values of the variable(s) it contains. A contradiction is an equation that has no solution because the statement is false for all values of the variable(s). An equivalent equation is formed when two equations have the same solution set. To solve problems involving equations, one typically begins by identifying the unknowns, determining the knowns, choosing the appropriate equation to use, and then solving for the unknown.