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Worksheets

Logarithms and Logarithmic Functions

Total questions: 25

Worksheet time: 1hrs 23mins

Name
Class
Date
1.
Rewrite 34 = 81 in logarithmic form.
a)
log34 = 81
b)
log813 = 4
c)
log381 = 4
d)
log481 = 3
2.
log525 = ?
a)
2
b)
5
c)
125
d)
10
3.
Change to Exponential Form:
log636 = 2
a)
26=36
b)
62=36
c)
362=6
d)
366=2
4.

Which equation is the inverse of the equation above?

f(x)=log3xf\left(x\right)=\log_3x  

a)

f1(x)=3xf^{-1}\left(x\right)=3^x  

b)

f1(x)=logx3f^{-1}\left(x\right)=\log_x3  

c)

f1(x)=x3f^{-1}\left(x\right)=x^3  

d)

f1(x)=3xf^{-1}\left(x\right)^{ }=3^{-x}  

5.
Write in logarithmic form:
45 = 1024
a)
log 4 1024 = 5
b)
log 5 1024 = 4
c)
log 4 5 = 1024
d)
log 5 4 = 1024
6.

Solve for x:

log4x=3\log_4x=3  

a)

44  

b)

1212  

c)

3232  

d)

6464  

7.

Find the approximate value of the logarithmic expression. Round your answer to the nearest whole number:

log101026\log_{10}1026  



(a)  

8.
Logarithmic functions are the inverse of...
a)
Linear Functions
b)
Exponential Functions 
c)
Quadratic Functions 
d)
Polynomial Functions 
9.

Evaluate: log6 1216=x\log_6\ \frac{1}{216}=x  

a)

x=3x=3  

b)

x=13x=\frac{1}{3}  

c)

x=13x=-\frac{1}{3}  

d)

x=3x=-3  

10.

Write an exponential function in the form y=abx y=ab^{x\ }  whose graph passes through (1, 8) and (3, 32).

a)

y=2(4)x y=2\left(4\right)^{x\ }  

b)

y=4(2)xy=4\left(2\right)^x  

c)

y=4(12) xy=4\left(\frac{1}{2}\right)^{\ x}  

d)

y=2(14)x y=2\left(\frac{1}{4}\right)^{x\ }  

11.

Write an exponential function in the form y=abx y=ab^{x\ }  whose graph passes through (1, 1) and (4, 8).

a)

y=2x y=2^{x\ }  

b)

y=2(2)x y=2\left(2\right)^{x\ }  

c)

y=2(12)x y=2\left(\frac{1}{2}\right)^{x\ }  

d)

y=12(2)x y=\frac{1}{2}\left(2\right)^{x\ }  

12.

Find the value of x.

12=log9x\frac{1}{2}=\log_9x  

a)

3-3  

b)

33  

c)

13\frac{1}{3}  

d)

13-\frac{1}{3}  

13.

Find the value of x.

13=logx4\frac{1}{3}=\log_x4  

a)

x=64x=64  

b)

x=12x=12  

c)

x=81x=81  

d)

x=16x=16  

14.

Find the value of x.

logx 18=3\log_x\ \frac{1}{8}=-3  

a)

x=3x=-3  

b)

x=3x=3  

c)

x=2x=-2  

d)

x=2x=2  

15.

FInd the inverse of

f(x)=log(x3)f\left(x\right)=\log_{ }\left(\frac{x}{3}\right)  

a)

f1(x)=3(10y )f^{-1}\left(x\right)=3\left(10^y\ \right)  

b)

f1(x)=10y f^{-1}\left(x\right)=10^y\  

c)

f1(x)=30y f^{-1}\left(x\right)=30^y\  

d)

f1(x)=10(3y )f^{-1}\left(x\right)=10\left(3^y\ \right)  

16.

Find the inverse of

y=ln(x5)y=\ln\left(x-5\right)  

a)

y=ex+5y=e^x+5  

b)

y=ex5y=e^x-5  

c)

y=5exy=5e^x  

d)

y=5exy=-5e^x  

17.

The wind speed s (in miles per hour) near the center of a tornado can be modeled by s=93logd+65s=93\log d+65  where d is the distance (in miles) that the tornado travels.

A tornado traveled 35 miles. Estimate the wind speed near the center of the tornado.

a)

s=208.6 mihs=208.6\ \frac{mi}{h}  

b)

s=200.8 mihs=200.8\ \frac{mi}{h}  

c)

s=206.8 mihs=206.8\ \frac{mi}{h}  

d)

s=286.0 mihs=286.0\ \frac{mi}{h}  

18.

The wind speed s (in miles per hour) near the center of a tornado can be modeled by s=93logd+65s=93\log d+65  where d is the distance (in miles) that the tornado travels.

The wind speed near the center of a tornado was 150 miles per hour. Find the distance that the tornado traveled.

a)

d=6.8 milesd=6.8\ miles  

b)

d=8.2 milesd=8.2\ miles  

c)

d=9 milesd=9\ miles  

d)

d=86 milesd=86\ miles  

19.

The decibel level D of sound is given by the equation D=10log(I1012)D=10\log\left(\frac{I}{10^{-12}}\right)  where I is the intensity of the sound. What is the decibel level when the intensity of the sound is 10810^{-8}  ?

a)

D=4 decibelsD=4\ decibels  

b)

D=10 decibelsD=10\ decibels  

c)

D=40 decibelsD=40\ decibels  

d)

D=1000 decibelsD=1000\ decibels  

20.

The decibel level D of sound is given by the equation D=10log(I1012)D=10\log\left(\frac{I}{10^{-12}}\right)  where I is the intensity of the sound. The pain threshold for sound is 125 decibels. Does a sound with an intensity of 10310^{-3}   exceed the pain threshold? Explain. Attach your explanation.

(a)  

21.

M=23logE9.9M=\frac{2}{3}\log E-9.9  

Find the inverse of the given function. Describe what the inverse represents. (image from BigIdea Math)

4 lines
22.

Find the inverse of

y=13+logxy=13+\log x  

a)

y=10(x+13)y=10^{\left(x+13\right)}  

b)

y=10(x13)y=10^{\left(x-13\right)}  

c)

y=10x+13y=10^x+13  

d)

y=10x13y=10^x-13  

23.

Find the inverse of y=e(x4)y=e^{\left(x-4\right)}  

a)

y=lnx4y=\ln x-4  

b)

y=lnx+4y=\ln x+4  

c)

y=ln(x+4)y=\ln\left(x+4\right)  

d)

y=ln(x4)y=\ln\left(x-4\right)  

24.

Rewite the expression in exponential form

log1327=3\log_{\frac{1}{3}}27=-3  

a)

33=273^{-3}=27  

b)

(13)3=27\left(\frac{1}{3}\right)^{-3}=27  

c)

(13)3=27\left(\frac{1}{3}\right)^3=-27  

d)

(3)13=27\left(-3\right)^{\frac{1}{3}}=27  

25.

Evaluate log749x\log_749^x  

a)

2x2x  

b)

7x7x  

c)

xx  

d)

22