9. Plot on the coordinate plane the set of points $(p, q)$ such that the equation $x^{2}+2 p x+q=0$ has two roots, one of which is greater than 2, and the other is less than 0.
Answer: The interior of the angle formed by the lines $q=0$ and $q=-4 p-4$, which lies below the first and to the left of the second line (see figure).

![](https://cdn.mathpix.com/cropped/2024_05_06_66eaf7c16e11660247a6g-4.jpg?height=719&width=727&top_left_y=646&top_left_x=534)

Solution: The given condition is equivalent to the values of the polynomial $f(x)=x^{2}+2 p x+q$ being negative at the points $x=0$ and $x=2$. Therefore, $q<0$ and $q<-4-4 p$.