2021 · Q20
If 5^(x−1) = (2.5)^(log₁₀5), then what is the value of x ?
Elementary MathematicsAlgebra
- A1
- Blog₁₀2
- Clog₁₀5
- D2log₁₀5
Explanation
Taking log₁₀ of both sides: (x − 1)log₁₀5 = log₁₀5 · log₁₀2.5. Cancelling log₁₀5 gives x − 1 = log₁₀2.5 = log₁₀(25/10) = 2log₁₀5 − 1. Hence x = 2log₁₀5, which is option (d).