Your answer should be c if it is wrong try d. hope this helps :)
The last term is -100 so its either a or d.
Try a:-
(x^2 - 25)(x-2)(x - 2)
= x^2 - 25 (x^2 - 4x + 4)
= x^2 + 4x^3 + 4x^2 - 25x^2 + 100x - 100
= x^4 + 4x^3 - 21x^2 + 100x - 100
Its a.
The area of a square is equal to s^2 where s is the length of one side.
49=s^2.
Root both sides to isolate the variable.
7=s
Final answer: 7 ft