Hi
f(x) = -x^2 +2x+15
Finding x-intercepts when f(x)=0
-x^2 +2x+15 = 0
|Using Calculator
x = -3, 5 |x-intercepts P(-3,0) and Pt(5,0)
Finding vertex
Using the vertex form of a parabola,where(h,k) is the vertex
f(x) = -x^2 +2x+15 |completing square to put into vertex form
f(x) = -[(x-1)^2 -1] + 15
f(x) = -(x-1)^2 +1 + 15
f(x) = -(x-1)^2 + 16 Vertex is Pt(1,16)