Question

What is the the vertex of `y=2x^2 + 8x + 5`?

Answer 1

(-2,-3)

Explanation:

Well there are numerous ways to solve this but I'll tell you the shortest one (at least according to me).

When you see a parabola of form `y=ax^2+bx+c` the slope of its vertex is 0. We know that the formula of the slope of any instantaneous line is `dy/dx` so

`d(2x^2+8x+5)/dx=0`
On solving this we get `x=-2`

Put this in our original equation of parabola and `y=-3`

This coordinates of the vertex are (-2,-3)