# What is the maximum value that the graph of y= -x^2 +5x -1?

Aug 25, 2016

$y = \frac{21}{4}$

#### Explanation:

$y = - {x}^{2} + 5 x - 1$

$y ' = - 2 x + 5$

$y ' = 0 \implies x = \frac{5}{2} \implies y = \frac{21}{4}$

we know from the shape that it's a max but checking anyways....

$y ' ' = - 2 < 0$, so yes