Big points

last year tammy had $4,500 to invest in two savings accounts. one account earns 7% simple annual interest, and the other account earns 6% simple annual interest. at the end of the year, tammy had earned a total of $290 in interest from the two savings accounts.
part a write a system of two equations that could be used to find the amount of money invested in each account. let x represent the amount invested at 7%, and let y represent the amount invested at 6%.
part b solve the system of equations. how much did tammy have invested at each rate?

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