Like terms are are terms whose variables (and their exponents such as the 2 in x 2) are the same. In other words, terms that are "like" each other. Note: the coefficients (the numbers you multiply by, such as "5" in 5x) can be different.
So like in your picture x and x would be like terms... your picture helps as well to identify your like terms because your like terms have the same background color to there particular rectangle.
