Jika fungsi f (x) = x2 + (k + 2) x + c memiliki titik balik ( -3, 14), hitunglah nilai k dan c

f (x) = x² + (k + 2)x + c
a = 1
b = (k+2)
c = c

ordinat titik balik fungsi kuadrat adalah (-b/2a, f(-b/2a))

diketahui ordinat titik balik (-3, 14)
maka 
-b/2a = -3
b/2a = 3
(k+2)/2 = 3
k+ 2 = 6
k = 4

f (-b/2a) = 14
f(-3) = 14
14 = (-3)² + (4 + 2)(-3) + c
14 = 9 - 18 + c
c = 14 - 9 + 18
c = 23