A cell phone plan costs $21.70 per month for 500 minutes of talk time. It costs an additional $0.06 per minute for each minute over 500 minutes. To get e-mail access, it costs 30% of the price for 500 minutes of talk time. Your bill, which includes e-mail, is the same each month for 6 months. The total cost for all 6 months is $196.26. Write and solve an equation to find the number of minutes of talk time you use each month.

You use 487 minutes of talk time each month.

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

can you put the picture up?

step-by-step explanation: