What does "congruent" mean in this context?

Do you mean this: y=2(x-4)^2

or this: y=2(x-4)+2

or something else?

I'll GUESS that it's this: y=2(x-4)^2

This suggests a parabola oppening up and vertex at (4,0).

A "congruent" parabola, then, with the other requirements, might be y=-2(x-1)^2 - 3

Really, it goes straight to the heart of understanding the form of the equation. There isn't anything magic or calculation-intensive about it.