Difficulty: Medium
Correct Answer: 2
Explanation:
Introduction / Context:
We solve a logarithmic equation involving base 4 by converting the left-hand side with the power rule and equating arguments after combining using log identities.
Given Data / Assumptions:
Concept / Approach:
Use 2·log₄ x = log₄(x^2) and 1 = log₄ 4. Then sum on the right: log₄ 4 + log₄(x − 1) = log₄(4(x − 1)). Equate arguments of equal logs.
Step-by-Step Solution:
Verification / Alternative check:
Check domain: x = 2 > 1; substitute: 2·log₄ 2 = 2·(1/2) = 1; right side 1 + log₄ 1 = 1 + 0 = 1. Holds exactly.
Why Other Options Are Wrong:
1 violates the domain; 3 and 4 do not satisfy the quadratic; “no real solution” is incorrect since x = 2 is valid.
Common Pitfalls:
Forgetting to use log₄ 4 = 1 or mishandling the power rule can lead to an incorrect linear equation instead of the correct quadratic.
Final Answer:
2
Discussion & Comments