1. VARIABLE S IN ALGEBRA Lesson 1.1

2. Objective/ Essential Question Objective: By the end of this lesson, you will be able to answer the question: How do you evaluate a variable expression?

3. Key Vocabulary Words Variable: a letter that is used to represent one or more numbers Values: the numbers the variable represents Variable Expression: a collection of numbers, variables, and operations Evaluating the expression: replacing each variable by a number

4. Example One Evaluate the expression when y=2 A. 8y B. 10 y C. y+3 D. 14-y

5. Example 2

6. Example 3

7. Example 4 The simple interest earned by money P (called the principal) at an annual interest rate r and t years is given by Prt. You deposit $650 at a rate of 8% per year. How much simple interest will you earn after one half of a year?

8. Example 5 You plan to go hiking in the Jedediah Smith Redwoods State Park in California. You estimate you’ll hike at a rate of 2 miles per hour on a steep trail. How low will it take you to hike from Howland Hill Road along the Boy Scout Tree Trail and back?