Essential Question: How do we Evaluate Algebraic Expressions? (+ & -) U3D4

Variable: Is a quantity that can change or vary. Mathematicians use letters to represent variables. Constant: A quantity (number) that does not change. 6 + x Expression: Is a mathematical phrase involving constants, variables, and operation symbols. (no equal signs) Vocabulary

Steps to Evaluate Expressions Step 1: Identify the variable. (Letter) x Step 2: Put parentheses around the variable. 6 + (x) Step 3: Plug in the number for the variable. 6 + (3) Step 4: Evaluate (simplify) is x, When x is 3

Evaluate each expression for x=1, 2, and 3. xX (x) + 5(1) + 56 (x) + 5 (2) + 5 (3) Step 1: Identify the variable: X Step 2: Step 3: Step 4: Example 1:

y11 – y Evaluate each expression for y=3, 4, and (y) 11 - (3) (4) (5)6 Step 3: Step 1: Identify the variable: y Step 2: Step 4: Example 2:

n n – Evaluate each expression for n=3, 4, and 5. (n) - 7 (3) (4) (5) Step 1: Identify the variable: n Step 3: Step 2: Step 4: Example 3:

Evaluate each expression x= 3 and 5. 1.X x x=3 X=5 x=5 3.X x + 7 X=3 x=3 X=5 x=5

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