Chapter 4 Quadratic Functions and Factoring - 4.2 Graph Quadratic Function in Vertex or Intercept Form - 4.2 Exercises - Skill Practice - Page 249: 33

-4

This function is in the form $y=a(x-h)^2 +k$. Thus, we see that k will be the critical value. If $a$ is positive, k will be the minimum, while if $a$ is negative, k will be the maximum. Using this, we see that the given function has a minimum of -4.