Solve the equation .
Answer and explanation
Correct answer: D.
- Step 1: Combine: , so . Step 2. gives . Step 3. is rejected because of a negative number is undefined, leaving . **Answer: . Why not the others:** the option and keeps the invalid root; gives , not 8; gives , not 8.
Practise more Algebra and functions.
Free questions with an explanation for every one, and full timed A-Level UK (AQA, Edexcel, OCR) mock tests.