Chapter 1, Equations and Inequalities - 1.2 Evaluate and Simplify Algebraic Expressions - 1.2 Exercises - Skill Practice - Page 14: 51

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We first write the expression that has three coefficients, two like terms, and one constant term: $$ 3x^2 + 10x + 5x^2 +3$$ Recall, like terms must (1) be raised to the same power and (2) consist of the same variable (i.e. x and y are not like terms). It is also important to note that numbers are all like terms with each other when not multiplied by anything. Thus, combining like terms, we obtain: $$8x^2 +10x+3$$