2. Essential Question: How do we Evaluate Algebraic Expressions? (● & /) U3D5

3. Variable: Is a quantity that can change or vary. Mathematicians use letters to represent variables. Constant: A quantity (number) that does not change. 2w - 4 Expression: Is a mathematical phrase involving constants, variables, and operation symbols. (no equal signs) Vocabulary

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

5. x 4x - 8 6 7 8 Evaluate each expression for x=6, 7, and 8. 4(x) - 5 4(6) - 5 4(7) - 5 4(8) - 5 19 23 27 Step 1: Identify the variable: X Step 3: Step 2: Step 4: Example 1:

6. y 12/y + 2 2 4 6 Evaluate each expression for y=2, 4, and 6. Step 1: Identify the variable: Step 2: Step 3:Step 4: y 12/(y) + 2 12/(2) + 28 12/(4) + 2 5 12/(6) + 2 4 Example 2:

7. xx² + 12x18/x 1 2 3 Evaluate each expression for x=1, 2, and 3. (x)² + 1, 2(x), 18/(x) (1)² + 1 Step 1: x Step 2: 1 + 1 2 (2)² + 1 4 + 1 5 (3)² + 1 9 + 1 10 2(1) 2 2(2) 4 2(3) 6 18/(1) 18 18/(2) 9 18/(3) 6 Example 3:

8. Evaluate each expression x= 3, 5. 1.7x 2. 15/x X=3 x=3 X=5 x=5 3.-60/x 4. -3x X=3 x=3 X=5 x=5

9. Evaluate each expression for n = 3. 1.9n – 7 2.5(3n + 2n) 3.12 ● n/3

10. Summary Write an example of: How do we Evaluate Algebraic Expressions? (● & /)