-1 OR 5*5=25 --

Short answer (in a boolean/logical sense): True (or 1).

Why:

• -1 is nonzero, so it’s considered true.
• 5*5=25 is true.
• True OR True = True.

If you’re asking in a specific language, the result might differ:

• C/C++/Java with logical OR (||): 1 (true).
• Python with or: would evaluate to -1 (since -1 is truthy, it returns the first truthy operand).
• Bitwise OR (−1 | 1): yields −1 (because −1 has all bits set).

Which context are you studying? I can tailor the explanation to that language.