Rosalie doit choisir le forfait le plus avantageux pour l'usage de son téléphone cellulaire, La compagnie A offre un tarif mensuel de 0,45 $/min. La compagnie B offre un tarif mensuel
de 0,40 $/min pour un maximum de 100 minutes, auquel s'ajoutent des frais de 0,25 $
pour chaque minute supplémentaire. Voici les durées des appels de Rosalie pendant
un mois représentatif de son utilisation habituelle.
7
15 min
240 s
1 min
0,4 h
h
2 min
0,35 h
4 min
h
20
10
Quelle compagnie Rosalie devrait-elle choisir ?​

let's cover over the formula of the vertex:

y = a(x – h)^2 + k

in this formula, (h,k) are the vertex, always remember that the positive or negative value of the vertex is based on the sign it has.

for example, if the vertex is -3,-6 then both the x and y value would have the positive sign attached to it and if it were a positive x and y value, then a negative sign would be attached to it.

with that being said, for our problem the x value is a positive one so we are looking for a number with a negative sign next to it, in this case the first and second choice.

however, for the first answer choice it isn't quite part of the formula so we know that the answer choice correctly displays the x value.

to confirm, we can see if the -1 fits correctly with the second answer choice, and as mentioned above a negative number will have a positive sign attached to it. so, for our problem we can see that -1 has been changed to +1, so we can confirm that the second answer choice is correct.

hence, our final answer is y=(x - 1)^2 + 1

final total: 63

step-by-step explanation:

60 times sales tax

60 times 0.05

3

60 + 3

63

you could deduce the conclusion directly using the facts pertaining to the specific situation.

hope this .