8. Jan needs to buy a backpack and several folders for school. If she shops at Smart
Supply, the backpack will cost $45 and folders
cost $0.45 each. If she shops at The Supply
Guys, the backpack will cost $50.40 and
folders cost $0.15 each. Write and solve an
inequality to find the number of folders Jan
would need to buy for The Supply Guys to be
the cheaper option.
9.
to
Mc
de
ine
th
th
Inequality:
Solution:

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