1) x = 5 2) x = 4 3) x = 15

1. Mental Math
Solve for x
1) 32
3x - 2
2)
= 16
1 = 64
2x-1
3) 3(52x - 9) = 375
4)
log81( 1 ) = x
3
5)
log8x = 3
2

2. Intro to Using Logs
We'll use log = log
button on calculator, called 'common log'
Can't rewrite as same base
Instead, we can take or apply logs to both sides and solve
= log15
Solve for x
Can NEVER rewrite as a power of 4
Can only solve by taking logs of both sides
2) Expand the logs
3) Solve for x