Jawabanmu

2014-05-30T20:37:31+07:00
f(x) = 3x^3 - 75x + 4
f(k) = 3(-k)^3 - 75(-k) + 4 = 4
-3k^3 + 75k = 0
-3k(k^2 - 25) = 0
-3k(k - 5)(k + 5) = 0
k = 0 atau k = 5 atau k = -5