If x=x2+6x-40 what are the values of x?

For f(x)=2x+1 and g(x)= x^2 -7, find (f•g)(x)

Atriangle with all sides of equal length is a/an triangle. a. right b. scalene c. equilateral d. isosceles

When solving this problem: 3025/5.5 = a/90.75 you get 49912.5 which would be the length of one of the sides of a square when the area is only 90.75 inches. is that answer correct, why, and how is it possible?