The graph represents the balance on Harrison’s car loan in the months since purchasing the car. A coordinate plane showing Car Loan Payments. The x-axis shows Months since Purchase and the y-axis shows Loan Balance in dollars. There is a straight line that starts at (0, 7,000) and passes through (2, 6,500), (4, 6,000), and (26, 500).
Which statement describes the slope of the line?

The loan balance decreases $500 per month.
Harrison makes a monthly payment of $250.
The loan balance increases $250 per month.
Harrison increases his monthly payment by $500 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