Anne has $5000 in her savings account and decides to leave there for three years. After one year the account increases by 10%, the following year it decreases by 5% and in the third year it increase by 15%. How much is in the account after three years?

$6000

increases by 10% but you then take away 5% fron the 10 as it decreases by 5. meaning you have incresed by 5% and adding the 15% equals 20%. so the account increases by 20%. 20% of 5000 equals 1000. add the two together and you get 6000. so the account total now is $6000

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