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

Nov 26, 2015

The vertex is $\left(- \frac{3}{10} , \frac{9}{20}\right)$

#### Explanation:

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

$- 10 x - 3 = 0 \setminus \iff x = - \frac{3}{10}$.

So, the vertex has $x$-coordinate $- \frac{3}{10}$. To find the $y$-coordinate, simply compute

$f \left(- \frac{3}{10}\right) = \frac{9}{20}$