Find the roots (the solutions when $y = 0$) of each of the following polynomial functions.

1. $y = x^{2} − 6x + 8$ 

   Hint (a):

   Factor the right side and use the Zero Product Property.

   Answer (a):

   $x = 2, x = 4$

2. $f\left(x\right) = x^{2} − 6x + 9$ 

   Hint (b):

   The roots are the $x-$intercepts on the graph of the function.

   Answer (b):

   $x = 3$

3. $y = x^{3} − 4x$ 

   Hint (c):

   $x$ is a common factor.

   More Help (c):

   See part (a).