How much do 15 DVDs cost at the store with the lowest unit price? Bernie's Bargains 6 DVDs for $56.70

Greg's Giveaways 10 DVDs for $99.70

Stan's Steals 8 DVDs for $79.68

Total cost= $141.75

Step-by-step explanation:

Giving the following information:

Bernie's Bargains 6 DVDs for $56.70

Greg's Giveaways 10 DVDs for $99.70

Stan's Steals 8 DVDs for $79.68

First, we need to determine the unitary price of each and choose the lowest one:

Bernie= 56.7/6= $9.45

Greg= 99.7/10= $9.7

Stan= 79.68/8= $9.96

The lowest price is $9.45.

Now, the total cost of 15 DVDs:

Total cost= 9.45*15

Total cost= $141.75

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