Logarithmic Equation Solution Count
XAT 2025 · Quantitative Ability & Data Interpretation · Medium · Logarithms
For how many distinct real values of does the equation below hold true? (Consider .)
- A.
1
- B.
Infinitely many
- C.
2
- D.
0
- E.
Depends on the value of a
Answer
E
Explanation
Simplify using change of base formula:
The equation becomes: . Discriminant , giving 2 real roots. However, the logarithmic terms require base and . If , the logarithm is undefined. Therefore, the existence of solutions depends on whether , i.e., depends on the value of .
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