How do you do x2 5x-25?

x2 + 5x - 25 does not have any factors, so if by "do"ing it you mean factoring it, it can not be done.

You can find the x-position of it's vertex by taking it's derivative and solving for zero:

f(x) = x2 + 5x - 25

f'(x) = 2x + 5

0 = 2x + 5

2x = -5

x = -2.5

So the vertex occurs where x = -2.5. The y co-ordinate at that point would be:

2.52 + 5(2.5) - 25

= 6.25 + 12.5 - 25

= 18.75 - 25

= -6.25

So the vertex of this curve occurs at the point (-2.5, -6.25). Because the highest power in the expression has a positive coefficient, we know also that the curve goes upwards.