Solve log x + log 5 = log 40.
Answer and explanation
Correct answer: B. 8
- Step 1: log x + log 5 = log 5x, so 5x = 40. Step 2. x = 8. Answer: 8. Why not the others: 35: That subtracts 5 from 40, which is not what the logs say. 200: That multiplies 40 by 5 instead of dividing. 45: That adds 5 to 40.
Practise more Indices and logarithms.
Free questions with an explanation for every one, and full timed Kenya KCSE mock tests.