Two trains leave the station at the same time one heading east one heading west. the eastbound train travels at 85 miles per hour. the westbound train travels at 105 miles per hour. how long will it take for the two trains to be 456 miles apart

 Train1 = 85 mph

Train 2 = 105mph

85+105 = 190 mph combined speed

Time = distance/ speed

Time = 456/190 = 2.4 hours = 2 hours and 24 minutes

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