Explanation:
log₁₀12.5 = log₁₀ 12¹/₂
= log₁₀²⁵/₂
= log₁₀25 - log₁₀2
= log₁₀5² - log₁₀2
= 2log₁₀5 - log₁₀2
= 2log₁₀¹⁰/₂ - log₁₀2
= 2(1-x)- x
= 2 - 2x – x
= 2 – 3x