In the equation \( C = 75h + 90 \), where:
- \( C \) represents the total cost of the car repair
- \( h \) represents the number of hours the mechanic works on your car
- 75 is the hourly rate charged by the mechanic
- 90 is the fixed cost for parts needed for the repair
The independent variable is the variable that you can control or change freely. In this case, the independent variable is \( h \), the number of hours of labor that the mechanic works on your car. The cost \( C \) depends on the value of \( h \), making \( h \) the independent variable.