Answer:
The parent function is
That Parabola's equation is
Step-by-step explanation:
I can't really explain much, but the top equation is a formula for <em>all </em>equations for a parabola. h and k are the x and y-values of the vertex. a is, well, a.
How did I find the equation of the parabola? Simple. Since the vertex is on the origin, h and k are 0. Also, because it intercepts (2,4) and (1,1), a=1.