School
7)
Seaside Bike Shop rents bikes for $10 plus $4 per hour. Jack paid $30 to rent a bike. Which equation, when solved for x, gives the
number of hours he rented the bike?

5 hr

Step-by-step explanation:

totalcost(x) = $10 + ($4/hr)x = $30

Solve this for x.  Start by subtracting $10 from boths sides, obtaining:

($4/hr)x = $30 - $10, or

($4/hr)x = $20

Dividing both sides by ($4/hr), we get x = ($20) / ($4/hr)  = 5 hr

take the logarithm of both sides (the base of the log doesn't matter):

apply the exponent property - this says that :

distribute the log terms on both sides:

group like terms together:

divide through both sides by the coefficient on :

you can do some additional rewriting here using the properties of the logarithm to simplify things if you like: