Common Logarithms

What is the understood base if no base is written in a logarithm? 
 $\log\ 100$  for example is log base __________ of 100.

• 2

• 1

• 100

• 10

I have to find the approximate solution to the problem  $\log_8\ 13.$  Which of the following would give me the result?

•  $\frac{\log13}{\log\ 8}$  

•  $\frac{\log8}{\log13}$  

•  $\log13-\log8$  

•  $\log8+\log13$  

Use your calculator to solve.  Round to four decimal places.

 $\log_7\ 5$   

• 0.8271

• 1.2091

• 0.1461

• 1.5441

Which of the following are equivalent to x in the equation  $5^x=25?$  Select all that apply.

•  $2$  

•  $\log_{25}\ 5$  

•  $\log_5\ 25$  

•  $\frac{\log25}{\log5}$  

•  $\frac{\log5}{\log25}$  

Use your calculator and evaluate  $\log_2\ 9.$  Round your answer to four decimal places.

Solve. Round to four decimal places.
 $9^x=45$  

Solve. Round to four decimal places.

 $8.2^{n-3^{ }}=42.5$  

 $n=$  _______________

The expression  $\log\left(x-5\right)\$  is undefined for all values of x such that...

•  $x\le5$  

•  $x>5$  

•  $x\le0$  

•  $x>1$  

If  $2^4=3^x,$  then what is the value of x? 

• 0.63

• 2.34

• 2.52

• 4

Solve. Round your answer to four decimal places.
 $5^x=52$  
 $x=$  __________________