How do you recognize identity in algebra?

In algebra, an identify is an equation which is always true, no mater what value you plug in for the variable. You can recognize an identity because when you solve it, you get out a true statement.

Here is an example:

3 + 2x = 3(1+x) - x

Distribute:

3 + 2x = 3 + 3x - x

Combine like terms:

3 + 2x = 3 + 2x

Subtract 2x from each side: 3 = 3

3 = 3 is a true statement, so the equation is an identity.