Superlesson
Project 9-3
Algebra
Chapter 9
Quadratic Functions and Equations
Sometimes graphing, using tables, and factoring cannot lead us to exact
solutions to a quadratic equation. How else can we get the solution? Let's
investigate!
Part A, Solving with Square Roots
1. Look at the Stockmaster Web site:
a. Choose any three mutual funds. For each fund, look at the earnings chart and record the approximate cost of the fund on January 1, 1998,
b. What would the interest rate be if you invested $1000 and earned $1200 assuming the interest compounded annually for a two year period?
Part B, The Quadratic Formula
2. Look back to the three mutual funds you investigated above. Calculate the percent return on your three funds for this year.
a. How much interest would be earned in a 2-year period if $1000 were invested in each of your funds and they compounded annually?
b. If $300 were earned over a 2-year period and your funds compounded annually, use the quadratic formula to calculate the rate of return on your $1000 investment.
Part C, Making Connections
3. Explain why the quadratic formula can be more useful than other methods for solving quadratic equations.