We should start by finding how much she did use:
7/8 * 400 = 350 feet used
To find how much she has left, subtract 350 from 400 to get 50 feet.
The answer is A. I calculated it and the vertex came out 2, -25 and the intercept was -3,7
Sub in what X and y are:

. Solve the exponents (if the exponent is 2 multiply the whole number by itself twice, if it were 3 you would multiply the whole number by itself three times): 3·3=9, 3·3=9: 9(9)= 81. :)