y=x²-4x-6=x²-4x+4-4-6=(x-2)²-10 in the form of m(x-h)²+k, where (h,k) is the vertex.
So y+10=(x-2)² has vertex at (2,-10).
y-intercept is found by putting x=0 in the original equation, so y=-6 is the y-intercept.
Axis of symmetry is x coord of vertex, x=2. The vertex is the minimum of the curve so the y value has a minimum value of -10, making the range for y [-10,∞).
The domain is (-∞,∞) for x,