The graph of which function will have a maximum and a y-intercept of 4?

a. f (x) = 4x2 + 6x - 1

b. f (x) = - 4x2 + 8x + 5

c. f (x) = - x2 + 2x + 4

d. f (x) = x2 + 4x - 4

The y-intercept of the equation is the value of the variable y or in this case, f (x), when x is equated to zero. Out of all the choices presented in this item, if x is equated to zero, the first two terms will be equal to zero, leaving the third term only for the numerical value of f (x).

From the choices presented, the answer would be f (x) = - x2 + 2x + 4. Thus, the answer is the third choice, C.