1. Calculators and logs Logarithmic equations
Logarithms (3)
Calculators and logs
Logarithmic equations

2. Using your calculator…
The log key on your calculator works out logs to base 10.
What would you expect your calculator output if you input the following:
Log(100)
Log(1000)
Log(1)

3. Solving log equations Solve 3x = 35 Take log of both sides
For convenience we use log10
Take log of both sides
Using log laws
Re-arrange
Using your calculator

4. Solving log equations Solve 53x+7 = 89 Take log of both sides
Using log laws
Re-arrange
Using your calculator
Solving…

5. Solve the following.. Activity 1 Time allowed – 5 minutes x = 2.23
43x+1 = 5x

6. Activity 2
Time allowed – 5 minutes
I earn 3% interest on my savings per year. How long will it take for me to double my savings?