1. substitute in for parabola, substituting for the same equation does nothing
2. the factors for y^2+y-20 are (y+5)(y-4)
3. solutions are y=4 or -5
4. substituting y=-5 in the equation
-5 = x^2 -5
0=x^2
x=0
therefore the three points of intersection are (0,-5), (-3,4), (3,4)
