Question 310681
Let the point (x,y) = your vertex

We use x = -b/2b to find x.

Let x = line of symmetry

Let a = 5 (the number in front of x^2) and b = 0 since there is no be term.

x = -(0)/2(5)

x = 0/10

x = 0....This is your line of symmetry.  This line evenly divides the parabola formed by the function f(x) = 5x^2 on the xy-plane.

To find your vertex, replace x with 0 in your function and solve for y.

But, where is y?

We can write y as f(x) or vice-versa.  They both mean the same thing.

y = 5(0)^2

y = 5(0)

y = 0

Your vertex is the point (0,0).  This parabola opens UPWARD and has a minimum point at the origin, which is represented by (0,0).

Understand?