No 28,29,30 apa ya tolong dijawab ya

28) f(x) = y
p = (-1)^2 - 2(-1) - 15
= 1 + 2 - 15
= -12 (B)

29) f(x) = -x^2 + 4x + k = -5
= x^2 - 4x + 5 = -k
(x-5) (x+1)
x = 5 atau x = -1

pakai yg x = -1
-x^2 + 4x + k = -5
k = (-1)^2 - 4(-1) - 5
= 1 + 4 - 5
= 0 (D)