alleryIf log x = log 5 + 2 log 3 - log 9, then x equals
A5
B45
C9
D15
Answer & Solution
Correct answer: A. 5
1. Use log a + log b = log(ab) and n log a = log(a^n).
2. RHS = log 5 + log 9 - log 9 = log 5.
3. So log x = log 5, meaning x = 5.
4. The 2 log 3 expanded to log 9 cancels the -log 9 term.
_Source: ICAI BoS Foundation Paper 3, Ch 1 Unit IV 'Logarithms', p.18 examples_
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