Question

a parabola has a vertex (5,-5) and also passes through the point (9,5). Write the equation of the parabola

Answer 1

The general equation of a parabola in vertex form is:
y = a(x-h)^2 + k where (h,k) is the vertex and a is a constant.

Here h = 5, k = -5
Substitute h,k above.

The parabola passes through (9,5)
put x = 9 and y = 5 and solve for a.