titik stasioner dari f (x) X3 + 6X2 + 9X + 7 tolong dibantu

f(x) = x³ + 6x² + 9x + 7

Syarat stasioner : f'(x) = 0
f'(x) = 0
3x² + 12x + 9 = 0
(3x + 3)(x + 3) = 0
x = -1 atau x = -3

Utk x1 = -1
y1 = f(-1) = (-1)³ + 6(-1)² + 9(-1) + 7
y1 = 3

Utk x2 = -3
y2 = f(-3) = -27 + 54 - 27 + 7
y2 = 7

Titik stasioner :
(x1,y1) = (-1,3)
dan
(x2,y2) = (-3,7)