Flashcard 6 - Next Generation Quantitative Reasoning, Algebra, and Statistics Flashcard Set for the ACCUPLACER Test

They must be of the same type. Real numbers can only combine with real numbers.
Variables must be of the same degree (raised to the same exponent) in order to be combined:
In this equation, \(x^2 + 2x^2 = 3x^2\), \(x^2 + 2x^3\) cannot be combined.

Unless answer choices show non-simplified expressions, it is nearly always best to combine like terms in an equation or expression.