simplify expression with exponent? (x-25)^2

[Lyracian]

Salutations Readers,

I have been learning about simplifing expressions. However I am confused what to do when there is more than one item inside the brackets with an Exponent?

I was given the puzzle (x-25)^2 = X^2 -25

I can add 25 to each side as the first step, but I am not sure what to do next.

I think I get X^2 -625 + 25 = X^2

I am not sure if it should be +625 or -625... I think I am just missing something basic, but I can not fathom it out.

[stapel_eliz]

I was given the puzzle (x-25)^2 =...

Squaring is squaring, regardless of what is being squared!

. . . . .

Then multiply the polynomials to complete the simplification.