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 log4 1,024 = 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=8x+7

What is x=7?

100

Solve: log x = 3

What is 1000?

200

Write the equation log3 729 = 6 in exponential form.

What is 36=729 ?

200

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

What is log27 3 = 1/3 ?

200

If there are initially 3000 bacteria in a culture, and the number of bacteria decrease by 40% each hour, how many bacteria remain after 8 hours. Round to the nearest whole number.

What is 50 bacteria.

200

Solve: 25x-4=53x+1

What is x=-9 ?

200

log3 x = 5

What is x = 243 ?

300

Write the equation log 1000 = 3 in exponential form.

What is 103=1000 ?

300

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

What is log1/2 8 = -3

300

Use the formula R = log I , where R is the measurement of the Richter scale and I is the intensity, to find the Richter scale measurement of an earthquake with intensity 30,000,000. Round your answer to four decimal places.

What is 7.4771?

300

Solve: e2x=ex+4

What is x=4?

300

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

What is x= 54.60 ?

400

Rewrite the log in exponential form: log(3x) + log5 (12) = 4

What is 54 = 36x

400

Is the function y= .7x growth or decay and why?

What is decay because the growth factor is less than 1?

400

Mr. Strebler takes a job that has a starting pay of $52,350. If he gets a 4% raise every year, how much will he make per year after 15 years? Round to two decimal places.

What is $94,279.39

400

Solve: 3e3-x= 15 Round your answer to two decimal places.

What is x= 1.39 ?

400

Solve: 3 ln x - 7 = 4 Round your answer to two decimal places.

What is x= 39.12 ?

500

Condense into one log function: log(x) - log (13) + log (5) ?

What is log (5x/13??

500

Simplify ln e3x

What is 3x?

500

Mr. Strebler is saving to purchase a new home. He needs $15,000 for a down payment. If he invests $10,000 in a bank that has a 8% interest rate compounded quarterly, will he have enough money in 5 years? If not, then how much is he short?

What is no, he will not? He will be $140.53 short.

500

Solve: 102x+1 + 2 = 4 Round your answer to two decimal places.

What is x = -0.35 ?

500

Solve: log(x) + log(x+4) = 5 

(Hint: Check the solutions)

What is x=4 (x=-8 is extraneous)?