Answer:
d) -3
Explanation:
The equation of a parabola in vertex form is given as:
y = a(x - h)² + k. Where (h, k) is the vertex of the parabola.
Given that the vertex of the parabola is at (4,-3) i.e h = 4 and k = -3.
The equation of the parabola is given as:
y = a(x - 4)² + (-3)
y = a(x² - 8x + 16) - 3
y = ax² - 8ax + 16a - 3
Given that when x = 5, y = -6. i.e:
-6 = a(5)² - 8a(5) + 16a - 3
- 6 = 25a - 40a + 16a - 3
-6 + 3 = a
a = -3