For comparison, below are a few examples of unlike terms. The following two terms both have a single variable with an exponent of 1, but the terms are not alike since different variables are used. 17x, 17z Each y variable in the terms below has a different exponent, therefore these are unlike terms. 15y, 19y2, 31y5 Although both terms below have an x variable, only one term has the y variable, thus these are not like terms either. 19x, 14xy.