Answer:
The translation is left 4 units
Explanation:
we know that

Is a vertical parabola open upward with vertex at (15,3)

Is a vertical parabola open upward with vertex at (11,3)
so
The rule of the translation of (15,3) ----> (11,3) is equal to
(x,y) ----> (x-4,y)
That means ----> The translation is left 4 units