1. 1.1 Variables and Equations Objective: To Simplify numerical expressions and evaluate algebraic expressions.

2. Variable Symbol used to represent one or more numbers Example: x, y, z, a, b, c – The numbers themselves are called the values of the variables – A variable expression is an expression that contains a variable Example: 2x + 4 – An expression that contains only numbers is called a numerical expression Example: 3 + 5

3. Notation 5 × y can be written as 5y or 5  y or 5(y) To show that a numerical expression has been simplified, please use an = Example 4 + 7 4 + 7 = 11

4. Substitution An expression may be replaced by another expression that has the same value

5. Example 1 (42÷6)+8 (42÷6)+8 = 7 + 8 (42÷6)+8 = 7 + 8 = 15 Or (42÷6)+8 7+8 15

6. Example 2 Evaluate the expression if a = 4 a.) 7a b.) (3a) + 2 7(4) (3  4)+2 28 12+2 14

7. Example 3 Evaluate (5x) – (3 + y) if x = 12 and y = 9 (5x) – (3 + y) (5  12)-(3+9) 60-12 48

8. Class Practice Oral Ex. P. 3 1-26

9. Homework Written Ex Page 3-4 1-49 odd