To rent a limousine, Theo must pay an initial fee of $
45
in addition to
$
12
for every hour (
h
) he has the limousine reserved. To calculate the final cost (
c
), Theo wrote the following equation.

c
=
45
+
12
h
If the final bill amounts to
$
123
, how many hours did Theo have the limousine reserved

6.5 hours

Step-by-step explanation:

123-45=78

78/12=6.5

the solution of the equation is 2.23 ⇒ answer b

step-by-step explanation:

* lets revise the meaning of exponential function

- the form of the exponential function is y = ab^x, where a ≠ 0, b > 0 ,  

  b ≠ 1, and x is any real number

- it has a constant base b

- it has a variable exponent x

- to solve an exponential equation, take the log or ln of both sides,  

  and solve for the variable

* lets solve the problem

∵

- the base is 7 and the exponent is x

- insert ㏑ in both sides

∴

- use the rule

∴ x ㏑(7) = ㏑(77)

- to find x divide both sides by ㏑(7)

∴

* the solution of the equation is 2.23 to the nearest 2 decimal places