A ferry operator takes tourists to an island. the operator carries an average of 500 people per day for a round trip fare of $20. The operator estimates that for each $1 increase in fare,20 fewer people will take the trip. What fare will maximize the number of people taking the ferry?

just sum

10 + 10 = 20

guess at question:

a vertical line intersects the graph of g(x,y) = 0 at two points. what conclusion follows about the function f(x) implicitly defined by g(x,f(x)) = 0?

the domain of f(x) cannot include the x coordinate of any such vertical line.

informally, f(x) is not a function, and

g(x,y)=0 cannot be solved for y uniquely.

the relation r = {(x,y) such that g(x,y) = 0} is a function if

for all (a,b) ∊ r and (c,d) ∊ r, a=c implies b=d.

step-by-step explanation: