• common logarithm
• Change of Base Formula
Find Common Logarithms
A. Use a calculator to evaluate log 6 to the nearest
ten-thousandth.
Keystrokes: LOG
Answer: about 0.7782
6
ENTER
.7781512504
A. Which value is approximately equivalent to log 5?
A. 0.3010
B. 0.6990
0%
B
A
0%
A
B
C
0%
D
D
D. 100,000.0000
A.
B.
C.
0%
D.
C
C. 5.0000
Find Common Logarithms
B. Use a calculator to evaluate log 0.35 to the
nearest ten-thousandth.
Keystrokes: LOG
.35 ENTER
Answer: about –0.4559
–.4559319556
B. Which value is approximately equivalent to
log 0.62?
A. –0.2076
A
0%
0%
B
D. 4.1687
A
B
C
0%
D
D
C. 1.2076
A.
B.
C.
0%
D.
C
B. 0.6200
Solve Exponential Equations Using Logarithms
Solve 5x = 62. Round to the nearest ten-thousandth.
5x = 62
log 5x = log 62
x log 5 = log 62
Original equation
Property of Equality
for Logarithms
Power Property of
Logarithms
Divide each side by log 5.
x ≈ 2.5643
Answer: about 2.5643
Use a calculator.
What is the solution to the equation 3x = 17?
A. x = 0.3878
B. x = 2.5713
0%
B
A
0%
A
B
C
0%
D
D
D. x = 5.6667
A.
B.
C.
0%
D.
C
C. x = 2.5789
Solve Exponential Inequalities Using
Logarithms
Solve 37x > 25x – 3. Round to the nearest
ten-thousandth.
37x > 25x – 3
log 37x > log 25x – 3
7x log 3 > (5x – 3) log 2
Original
inequality
Property of
Inequality for
Logarithmic
Functions
Power Property
of Logarithms
Solve Exponential Inequalities Using
Logarithms
7x log 3 > 5x log 2 – 3 log 2 Distributive
Property
7x log 3 – 5x log 2 > – 3 log 2
Subtract 5x log 2
from each side.
x(7 log 3 – 5 log 2) > –3 log 2
Distributive
Property
Solve Exponential Inequalities Using
Logarithms
Divide each side by
7 log 3 – 5 log 2.
Use a calculator.
x > –0.4922
Simplify.
What is the solution to 53x < 10x –2?
A. {x | x > –1.8233}
B. {x | x < 0.9538}
0%
B
A
0%
A
B
C
0%
D
D
D. {x | x < –1.8233}
A.
B.
C.
0%
D.
C
C. {x | x > –0.9538}
Change of Base Formula
Express log5 140 in terms of common logarithms.
Then round to the nearest ten-thousandth.
Change of Base Formula
Use a calculator.
Answer: The value of log5 140 is approximately 3.0704.
What is log5 16 expressed in terms of common
logarithms?
A.
A
0%
0%
B
D.
A
B
C
0%
D
D
C.
A.
B.
C.
0%
D.
C
B.