Answer:
see below
Explanation:
y = x^2 +2x - 8
Factor
y = ( x+4)(x-2)
The zeros are
x+4 = 0 x-2 = 0
x= -4 x= 2
(-4,0) (2,0)
The axis of symmetry is 1/2 way between the zeros
(-4+2)/2 = -2/2 = -1
x = -1
The x coordinate of the vertex is at the axis of symmetry
The y value is found by substituting x=-1
y = (-1+4) (-1-2)= 3*-3 = -9
Vertex ( -1,-9)
The domain is all real numbers
The range is from -9 up
y≥ -9 since it opens upward