Next, to see this equation on a calculator we actually have to use two separate functions. This is because a sideways parabola is not a function — think back to the Vertical Line Test.
y=sqrt(5x+40) and y=- sqrt(5x+40)
To enter these functions, push Y= and type them in two different rows. Then, push GRAPH to draw them.
Looking at the graph, we can see that the vertex occurs at (- 8,0) and that the parabola opens to the right.
