Math 30-2
Exponential Functions: Lesson #5
Solving Exponential Equations by Graphing
Objective: By the end of this lesson, you should be able to:
- solve an exponential equation by graphing
What is an exponential equation?
To Solve an Exponential Equation by Graphing:

Graph Y1 =
Y2 =

Adjust the window settings so that you can see the point of intersection.

Find the point of intersection:
The solution is the _____________________ of the point of intersection.
e.g. 1) Solve the following exponential equations by graphing. Round to the nearest hundredth
if necessary.
x
a) 1.5 x  7
c) 8 x  2 x 3
Verify your solution for part c.
`
b) 3 2  243
Math 30-2
Exponential Functions: Lesson #5
e.g. 2) Darryl makes monthly payments of $1600 on his $250 000 mortgage. The interest rate
for his mortgage is 6%/a compounded semi-annually. The number of months it will take
him to pay off the mortgage is given by the equation:
1.004938622n  0.228340313
where n is the number of months.
a) Solve the equation to determine how many months it will take Darryl to pay off his
mortgage. How many years is this?
b) How much will Darryl have paid in total on the mortgage?
c) How much interest will he have paid?
Assignment:
p. 362-363 #5, 8-9
p. 395-399 #3, 11, 16-17, 19-20