June 2025 Paper 2 Q4
4 Solve the equation
\[5^{x-1} = 20\]Give your answer in an exact form. [2 marks]
| Scheme | Marks | AO |
|---|---|---|
| Takes logs with the same base of both sides. Can be any base Or Writes 20 as a power of 5. E.g. \(5^{\text{AWRT } 1.9}\) | M1 | 1.1a |
| Obtains the correct exact value ACF | A1 | 1.1b |
| (2 marks) |