What is the co-ordinates of the minimum point of the quadratic equation x^2+6x-16?

Well this can be rewritten as : (x+8)(x-2), so roots are x=-8, and x=2. So therefore the x co-ordinate of the minimum point is half way between the 2 roots by symmetry. So the x co-ordinate is x=-3. Substituting this into the original equation gives -25. Therefore the minimum point is (-3,-25).