Question

What is the vertex of `y= -5x^2 − 3x`?

Answer 1

The vertex is `(-3/10, 9/20)`

Explanation:

The vertex is the maximum of this parabola: so derive it, and set the derivative to zero:

`-10x-3=0 \iff x=-3/10`.

So, the vertex has `x`-coordinate `-3/10`. To find the `y`-coordinate, simply compute

`f(-3/10)=9/20`