If (f(x) = mx^{2} – 6x – 3) and (f'(1) = 12), find the value of the constant m.

**A.**

9**B.**

3**C.**

-3**D.**

-4

##### Correct Answer: Option A

##### Explanation

(f(x) = mx^{2} – 6x – 3)

(f ‘(x) = frac{mathrm d y}{mathrm d x} = 2mx – 6)

(f'(1) = 2m – 6 = 12)

(2m = 18 implies m = 9)