Answer:
See below ~
Step-by-step explanation:
Finding the x-intercepts :
- y = 0 is the condition for an x-intercept
- 0 = -(x + 3)(x + 5)
- x + 3 = 0 ⇒ x = -3
- x + 5 = 0 ⇒ x = -5
- The x-intercepts are : (-3, 0) and (-5, 0)
Finding the vertex :
- Expand the polynomial
- y = -(x + 3)(x + 5)
- y = -(x² + 3x + 5x + 15)
- y = -(x² + 8x + 15)
- y = -x² - 8x - 15
- Vertex = (h, k)
- h = -b/2a = 8/2(-1) = -4
- k = -D/4a
- k = -(-4 + 3)(-4 + 5)
- k = -(-1)(1)
- k = 1
- The vertex is : (-4, 1)
