# How do you find the axis of symmetry, and the maximum or minimum value of the function y=x^2-4x+7?

##### 1 Answer
Jun 25, 2016

the axis of simmetry is $x = 2$ and the minimum value is in x=2

#### Explanation:

Since the equation of the axis is

$x = - \frac{b}{2} a$

when

$y = a {x}^{2} + b x + c$

and, in this case, a=1 and b=-4,

the axis of simmetry is

$x = \frac{4}{2} = 2$

Then, since

$y ' = 2 x - 4$

and y'=0 when x=2

the minimum value is in x=2