1. = Today’s Objective To be able to evaluate variable expressions
What’s the difference between an expression and an equation? =

2. Expressions compared to Equations
8y, 16a/b, 4r + s, 7
Equations
3x + 4 = 6
3r = 9

3. Vocabulary
Variable = A letter or symbol that is used to represent a number
Evaluating an expression = Replacing all the variables in an expression with a number
Value of an expression = The result of the expression when you evaluate it.

4. Steps for evaluating expressions
Write the expression
Substitute the values
Simplify the expression

5. 1.) Evaluate 5x + 4y when x = 3 and y = 2
5(3) + 4(2) 23

6. 2.) Evaluate x + (2x -1) when x = 3
3 + (2(3) - 1) 8

7. Vocabulary What’s the difference between a term and a factor?
In the expression 3x + 2, 3x and 2 are called terms of the expression.
In the expression 4x , 4 and x are called factors of the expression.
What’s the difference between a term and a factor?

8. Substitute 75 for r and 1.5 for t
3.) Find the distance traveled using the distance formula d = rt, when r = 75 & t = 1.5
Substitute 75 for r and 1.5 for t
d = rt
d =(75)(1.5)
d = 112.5