Logs!
Exponential EQ's
Word Problems
Solving Exponential EQ's
Solving Log EQ's
100

Simplify the expression: log28

What is 3?

100

Write the exponential equation 45= 1,024 in logarithmic form.

What is log41,024=5?

100

If there are initially 3000 bacteria in a culture, and the number of bacteria increase by 25% each hour, how many bacteria will there be in 5 hours? Round to the nearest whole number.

What is 9,155 bacteria?

100

Solve: 82x=8(x+7)

What is x=7?

100

Solve: log x = 3

What is 1000?

200

Write the equation log3729 = 6 in exponential form.

What is 36=729 ?

200

Write the exponential equation 271/3= 3 in logarithmic form.

What is log273 = 1/3?

200

If there are initially 3000 bacteria in a culture, and the number of bacteria increase by 25% each hour, after how many hours will you reach approximately 5,850 bacteria?

What is 3 hours?

200

Solve: 25(x-4)=5(3x+1)

What is x=-9 ?

200

log 3 x = 5

What is x = 243 ?

300

Write the equation log1000=3 in exponential form.

What is 103=1000?

300

Write the exponential equation (1/2)-3=8 in logarithmic form.

What is log1/28 = -3

300

You put $4000 into an account earning interest compounded continuously. After 6 years you have $5059.58. What percent interest did you earn?

3.88% interest

300

Solve: 10(2x+1) + 2 = 4 Round your answer to two decimal places.

What is x = -0.35 ?

300

Solve: ln x = 4 Round your answer to two decimal places.

What is x= 54.60 ?

400

What is the asymptote of the graph of f(x)=log(x-1)?

What is x=1 ?

400

Is the graph y= .7^x increasing or decreasing, and is it a function?

decreasing  

yes, a function

400

Determine how much time is required for an investment to triple in value if interest is earned at a rate of 6.25% compounded monthly?

17.62 years

400

Solve: 3e(3 - x)= 15 Round your answer to two decimal places.

What is x= 1.39 ?

400

log(8)-log(2x)=-1

x=40

500

What is the asymptote of the graph of f(x)=log(x+2)-1?

What is x= -2 ?

500

Simplify ln e3x

What is 3x?

500

Iodine-131 is used to find leaks in water pipes.  It has a half life of 8.14 days.  Write the exponential decay function for a 200 mg. sample.  Find the amount of Iodine-131 remaining after 72 days.

0.43 mg remaining

500

Solve: e2x -5ex+6=0

Round your answer to two decimal places.

x=ln3=1.1

x=ln2=.69

500

log (x+21)+ log(x) = 2

x=4

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