Answer:
Step-by-step explanation:
Let C(x) be the cost to produce x batches of widgets, and let R(x) be the revenue in thousands of dollars.
[tex]R(x) = -x^2 + 6x,\\ C(x) = x + 4.[/tex]
Profit function = Revenue - cost
So we get profit function by subtracting C(x) from R(x) using algebraic method of subtraction.
Profit function of x
= [tex]Pr(x) = R(x) -C(x)\\= -x^2+6x-x-4\\=-x^2+5x-4[/tex]