An appliance repair shop charges $80 for the first hour of labor and $65 for each additional hour. The total labor charge for an air-conditioning system installation with $665. Write and equation for finding the total repair time then solve the equation.
Chose the correct answer below:
A. (80+65)x=665
B. 65+80x=665
C. 80+65x=665
The total repair time is ___ hours.

C. 80+65x=665

The total repair time is 9 hours.

Step-by-step explanation:

The first hour is $80, no matter what. That is the first part of your equation.

x = the number of hours minus 1.

It would be -1 because it is $65 per ADDITIONAL hours, after the first hour.

So that would be 65x, because you don't know the number of hours it took (yet), but you know that it would be $65 per extra hour.

So you have your equation: 80+65x=665

1. Get rid of subtraction/addition.

You want to get rid of the number from both sides. It's subtracting 80 and not adding 80 because the 80 is positive, and you want to cancel out that 80.

80+65x=665

-80           -80

You are left with 65x=585

2. Get rid of multiplying/dividing.

Here, we want to get the variable by itself, so we will have to divide the 65x by 65. You want to do the opposite operation to cancel the 65 out.

65x=585

65x/65 = 585/65

You are left with x = 9