### Home > INT3 > Chapter 8 > Lesson 8.1.1 > Problem8-15

8-15.

What are the roots (the solutions when $y = 0$) of each of the following polynomial functions?

1. $y = x^{2} – 6x + 8$

Factor the right side and use the Zero Product Property.

$x = 2, x = 4$

1. $f\left(x\right) = x^{2} – 6x + 9$

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

$x = 3$

1. $y = x^{3} – 4x$

$x$ is a common factor.

See part (a).