-1' OR 5*5=25 or 'RLFgWRKv'='

That looks like an attempted SQL injection payload, not a math expression.

High-level notes (for exam context only, not for exploitation):

• 5*5=25 is a true condition in SQL (and in most languages: 25 = 25).
• If an attacker can inject into a vulnerable query, an OR clause containing a true condition can make the WHERE clause always return true (bypassing filters), provided the quote handling is such that the payload is parsed as part of the SQL.
• The -1' part tries to terminate a preceding string literal. If the application correctly uses parameterized queries, this would be harmless; if not, it could produce a syntax error or be exploited.
• The trailing =' suggests an incomplete comparison and would typically cause a syntax error unless a right-hand side value is supplied (e.g., ='abc' or ='').

Important safety note:

• I can’t assist with crafting or optimizing attack payloads. If you’re studying for an exam, focus on defense and safe testing.

Defense you should know for exams:

• Use parameterized queries / prepared statements everywhere. Do not build SQL by concatenating user input.
• Validate and sanitize input, with whitelisting for allowed formats and lengths.
• Use least-privilege database accounts and proper error handling (don’t leak DB errors to users).
• Consider using ORM layers or database drivers that bind parameters automatically.
• In labs, test with safe, explicit test cases or dedicated training platforms (e.g., DVWA, WebGoat, OWASP Juice Shop) rather than production systems.

If you want, I can:

• Explain how to rewrite a vulnerable query to a safe, parameterized version.
• Provide practice questions on SQL injection defense and boolean logic for exam prep.
• Analyze similar examples at a high level (without actionable exploitation steps).