3y2+2x-7 is an example of an algebraic expression. the letters y and x stand for numbers. 3y2, is short for 3 x y x y. 3 is the coefficient of y2. algebraic terms may be simplified by combining like terms. thus 3y2+2x-7x=3yx-5x since 2x and 7x are like terms (i.e both terms in x)