Find the minimum value of (y = x^{2} + 6x – 12).
-
A.
-21 -
B.
-12 -
C.
-6 -
D.
-3
Correct Answer: Option A
Explanation
(y = x^{2} + 6x – 12)
(frac{mathrm d y}{mathrm d x} = 2x + 6 = 0)
(2x = -6 implies x = -3)
(y(-3) = (-3)^{2} + 6(-3) – 12 = 9 – 18 – 12 = -21)