We must re-write the given equation in vertex form. "Vertex form" has this appearance: y-k = a(x-h)^2 (which applies to a vertical parabola).
Important: Please express "square of x" as x^2, not as x2.
We can re-write y = x^2 - 10x + 25, using "completing the square," as
y = (x-5)^2 + 0.
Multiply this out to verify that it does indeed equal x^2 - 10x + 25.
Then, in vertex form, the equation of this parabola is y - 0 = 1(x-5)^2.
The vertex (h,k) is at (5,0).