What is the y -value of the vertex of the function f of x is equal to negative open paren x minus 3 close paren times open paren x plus 11 close paren ?

The zeros are x = 3 and x = −11, so the vertex lies halfway between them at x = (3 + (−11))/2 = −4. Substituting x = −4 gives f(−4) = −(−4 − 3)(−4 + 11) = −(−7)(7) = 49. The y-value of the vertex is 49, choice C.

AI-written and checked against the verified answer.