Answer:
5
Step-by-step explanation:
Pretty self-explanatory
Answer:
a) 
b) 
Step-by-step explanation:
Use logarithm properties:

Then
a) 
b) 
You can multiply everything by 7 to make things simpler.
3x + 5 = 4
3x = -1
x = -1/3
0.75 miles per hour I think....
Last one!
explanation is I remember having this question and studying this bad in middle school :)