1. Review: 10.1a Mini-Quiz 1. Solve 5y = 125y2
2. Solve (7x + 2)2 – 81 = 0

2. Class Greeting

3. Chapter 10 Quadratic Equations and Functions
Lesson 10-1a
Solving Quadratic Equations by
Factoring and using the Square Root Property

4. Objective: Students will solve word problems by solving quadratic equations by factoring and using the square root property.

5. Example 1 – Calculating a Compound Interest Rate
Five hundred dollars ($500) is deposited in an account.
At the end of 2 years, the balance in the account is $720. The interest earned on the account is compounded annually. What is the interest rate?
Solution
The mathematical model used to find the interest earned on an account is
A = P(1 + r)t
where A is the balance in the account, P is the amount deposited, r is the annual interest rate (in decimal form), and t is the number of years.

6. Example 1 – Calculating a Compound Interest Rate
A = P(1 + r)t
720 = 500(1 + r)2
1.44 = (1 + r)2
1.2 = 1 + r
0.2 = r
So, the interest rate is 20%. Check this in the original statement of the problem.

7. Lesson Summary: Objective: Students will solve word problems by solving quadratic equations by factoring and using the square root property.

8. Preview of the next Lesson: Objective: Students will learn how to solve quadratic equations by completing the square.

9. Homework
/83-95 odd
#87: Don’t use 3.14 for pi and leave your answer as pi.
#89: Don’t use $ ; instead use $1690.
#95: Don’t use 5; instead use 270.

10. Stand Up Please