1. Warm-Up!
Log6 x + Log6 9 = Log6 54
Log4 (x-3) + Log4 (x+3) = 2

4. Common Logarithms
Base 10 logarithms are called common logarithms. Common logs are usually written without the subscript 10.
Log10 x = log x
Log to find press:
LOG 3
ENTER

5. Change of Base Formula
In order to evaluate logs with a calculator, you must convert them to common logarithms using the following formula:

6. Solve 3x = 11 Rewrite with a log in front of each side:
Move the exponent to the front:
Isolate the X:
Use the calculator:

7. log9 1043 Find the value of log9 1043
First of all – the calculator does not let use evaluate log base 9 – only log base 10
Therefore we need to change this into log base 10.
log9 1043

8. Use the change of base formula to change from base 9 to base 10:

9. Approximate to four decimal places Log2 13

10. Page 549/550 (17-22)(27-34)(45-48) Chapter 10 Test –
Tonight’s Homework:
Page 549/550
(17-22)(27-34)(45-48)
Chapter 10 Test –