anon: 25 to the power of -1/2
Whenever anything is raised to a negative power it is the same a the reciprocal being raised to a positive power.
so
25 to the power of -1/2 = 1 / (25 to the power of +1/2)
A power of a half is the same as a sqrt so this equals 1 / (sqrt25)
I am sure that you can finish it yourself