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MCQ practice · SSC General Mathematics Board questions · Chapter 4: Exponents and Logarithms

Cumilla Board 2025

Under what condition does aˣ = aʸ imply x = y?

Think it through first, then pick an option.

  1. a a < 0, a ≠ 1
  2. b a > 0, y < 1
  3. c a > 0, x > 1
  4. d a > 0, a ≠ 1
Answer and explanation

Correct answer: d a > 0, a ≠ 1

If a = 1 every index gives 1, so a ≠ 1 is needed; negative bases are excluded.

Why the other options are wrong

  • a a < 0, a ≠ 1: The base must be positive, not negative.
  • b a > 0, y < 1: The condition is on the base, not on the index y.
  • c a > 0, x > 1: The condition is on the base; x > 1 is not required.