CONCEPT PREVIEW Evaluate each expression. 3a - 2b, for a = -2 and b = -1

Key Concepts

Algebraic Expressions

Algebraic expressions are mathematical phrases that can include numbers, variables, and operators. In the expression 3a - 2b, 'a' and 'b' are variables that can take on different values. Understanding how to substitute values into these expressions is crucial for evaluating them correctly.

Substitution

Substitution is the process of replacing a variable in an expression with a specific value. In this case, substituting a = -2 and b = -1 into the expression 3a - 2b allows us to compute the value of the expression. This step is fundamental in simplifying and solving algebraic expressions.

Order of Operations

The order of operations is a set of rules that dictates the sequence in which calculations are performed in an expression. Commonly remembered by the acronym PEMDAS (Parentheses, Exponents, Multiplication and Division, Addition and Subtraction), following this order ensures that expressions are evaluated correctly and consistently.