Exercise 60 Page 287

We want to find the discriminant of the quadratic equation $a{x}^2+bx+c=0.$ Recall that for the quadratic equation, $b^2-4ac$ is the discriminant. Let's identify the values of $a,$ $b,$ and $c.$

$$\begin{array}{c}q{x}^2+rx+s=0\end{array}$$

We have that $a=q,$ $b=r$ and $c=s.$ Finally, let's evaluate the discriminant.

$b^2-4ac$

SubstituteValues

Substitute values

$r^2-4(q)(s)$

Multiply

Multiply

$r^2-4qs$

This corresponds to the answer C.