Question

mr. chen hires an electrician to install the light fixtures for an addition to his house. the electrician charges an initial fee plus an hourly rate for the number of hours it will take to complete the installation. the function y = 120 + 55x can be used to model the total cost of the job, in dollars. what is the independent variable in this situation, and what does it represent? $55; the electricians initial fee for the job $120; the electricians initial fee for the job x; the number of hours to complete the job y; the total cost of the job

Explanation:

In a linear - function of the form $y = mx + b$, the independent variable is the variable that can be freely changed. Here, the total cost $y$ depends on the number of hours $x$. The number of hours to complete the job can be varied independently, and it affects the total cost. The initial fee is a fixed amount ($120$) and the hourly rate ($55$) is multiplied by the number of hours $x$.

Answer:

C. $x$; the number of hours to complete the job