Find the coordinates of the vertex and the equation of the axis of symmetry of the parabola with the given equation.

Question

y = 8x^2 + 48x − 3
vertex
(x, y) =



axis of symmetry ________

Answer 1

y = 8(x^2+6x) - 3
now just complete the square.
y = 8(x^2+6x+9) - 3
but wait. You just added 8*9, so subtract it off so things don't get changed.

y = 8(x^2+6x+9) - 3 - 8*9
y = 8(x+3)^2 - 75

now it's easy to see that the vertex is at (-3,-75), and of course, it lies on the axis of symmetry.