Chapter 8.8, Problem 9OE

To determine

To find: Whether the graph of the given quadratic function opens upward or downward

Answer to Problem 9OE

The graph of the given quadratic function opens downward.

Explanation of Solution

Given information:

The given function is,

  $y=9-x^2$

Concept used:

For the quadratic equation, if the leading coefficient that is coefficient of $x^2$ is greater than zero then the graph opens in upward direction or if less than zero than opens in downward direction.

The given function is,

  $y=9-x^2$

The leading coefficient of the equation is $-1<0$ .

For the quadratic equation, if the leading coefficient that is coefficient of $x^2$ is greater than zero then the graph opens in upward direction or if less than zero than opens in downward direction.

Hence, the graph of the given quadratic function opens downward.