Answer: 4x + 100
Step-by-step explanation:
The company charges $4 per foot plus an installation charge of $100.
There is therefore both a fixed element and a variable element.
The fixed element is the $100 installation charge
The variable element is 4 * the number of square feet of carpet which is x: 4 * x
Formula puts them together to give:
= Variable cost + Fixed cost
= 4 * x + 100
= 4x + 100
