we are given the vertex of a parabola equal to (4, 0) and that the passes the point (6,1). In this case, it is assumed from the given that the parabola is facing upwards. In this case, the equation is (y-k) = 4a (x-h)^2 ; y = 4a (x-4)^2 when x is 6 and y is 1. then,
1 = 4a (6-4)^24a is equal to 1/4
the equation then is y = 1/4 (x-4)^2