Properties of Logarithms
Logarithmic Expressions
Change of base formula
Take logarithm in each side
Other
100

Use log 4 = 0.602 and log 12= 1.079 to evaluate the logarithm:

log 3

log 12- log 4 = 1.079- 0.602

= 0.477

100

Expand the expression:

log3 4x

= log4 + logx

100

Use the change of base formula to evaluate the logarithm:

log7

= 1.404

100

Solve:

8x = 20

= 1.44

100

Solve this logarithmic equation: 

log(4x - 7) = log5 (x + 5)  

= x = 4

200

Which logarithm has the same value as the expression: ln 6 + ln 2?

A. ln 64             C. ln 12 

B. ln 3               D. ln 36


C. ln 12

200

Expand the expression: 

log2/5

= log2 - log5

200

Use the change of base formula to evaluate the logarithm:

log5 14

= 1.640

200

Solve:

e-x = 5

= -1.61

200

Exponentiate each side of an equation: 

log4 (5x - 1) = 3

= x = 13

300

Use log 4 = 0.602 and log 12= 1.079 to evaluate the logarithm:

log 48

log 12 + log 4 = 1.079 + 0.602 

= 1.681

300

Expand the Expression:

log5x3yz2

= log7 5 + 3 logx + logy + log7 z2

300

Use the change of base formula to evaluate the logarithm:

log6 24/5

=0.875

300

Solve:

73x = 18

= 0.5

300

What is (are) the solution (s) of 

log 2x + log (x - 5) = 2? 

A. -5, 10       C. 10

B. 5              D. 5, 10

A. x = 10 or x = -5 

400

Use log 4 = 0.602 and log 12= 1.079 to evaluate the logarithm:

log 1/3

log 4/12 = log 4 - log 12 = 0.602 - 1.079

= -0.477

400

Expand the expression:

ln 6x2/y4

= ln 6 + 2 ln x - 4 ln y

400

Use the change of base formula to evaluate the logarithm:

log3 9/40

= -1.358

400

76x = 12

= 0.21

400

Solve by equating exponents:

4= (1/2) x-3

x = 1

500

Use log 4 = 0.602 and log 12= 1.079 to evaluate the logarithm: 

log 64

log 4= 3 log 4 = 3(0.602)

= 1.806

500

Expand the expression: 

log√ 9x

log3 + 1/2 log3x

500

Use the change of base formula to evaluate the logarithm:

log7 3/16

=-0.860

500

103x + 4 = 9

= 0.23

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