Susan purchased a prepaid phone card for $15. Long distance calls cost 14 cents a minute using this card. Susan used her card only once to make a long distance call. If the remaining credit on her card is $9.26, how many minutes did her call last?

41 minutes

Step-by-step explanation:

Step one:

given data

Susan purchased a prepaid phone card for $15

let the number of minutes be x

and let the total be y

per minute call cost = 14 cents = $0.14 per minute

Hence the expression for the situation is given as

y= 15-0.14x

Step two:

given that the balance after a call is 9.26

9.26=15-0.14x

solve for x

9.26-15= -0.14x

5.74=0.14x

divide both sides by 0.14

x=5.74/0.14

x=41 minutes

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: