Answer:
(x-3)(x+5) = 0
x-3 = 0 and x+5=0
x=3 and x=-5 when y=0
y = x^2+2x-15
complete the square
= x^2+2x + 1 -15 - 1
= (x+1)^2 -16
f(x) = y = (x+1)^2 -16
y intercept = -15 or the point (0,-15)
x intercepts = 3 and -5 = the two zeroes or roots, or the points (3,0) and (-5,0)
vertex or minimum point of the upward opening parabola is (-1,-16)
note the 2 zeroes are both 4 units horizontally from the vertex x value, 3 to -1 is 4, and -1 to -5 is 4.
the line of symmetry is x=-1. left and right of x=-1 are mirror images
Step-by-step explanation:
hope it helps
