| Date | November 2017 | Marks available | 5 | Reference code | 17N.1.hl.TZ0.1 |
| Level | HL only | Paper | 1 | Time zone | TZ0 |
| Command term | Solve | Question number | 1 | Adapted from | N/A |
Question
Solve the equation \({\log _2}(x + 3) + {\log _2}(x - 3) = 4\).
Markscheme
\({\log _2}(x + 3) + {\log _2}(x - 3) = 4\)
\({\log _2}({x^2} - 9) = 4\) (M1)
\({x^2} - 9 = {2^4}{\text{ }}( = 16)\) M1A1
\({x^2} = 25\)
\(x = \pm 5\) (A1)
\(x = 5\) A1
[5 marks]
Examiners report
[N/A]
