9709 P12 - Jun 2020 - Q5 - 6 marks
677
For real \(x\), \(f(x)=a-2x\), where \(a\) is constant.
(a) Express \(ff(x)\) and \(f^{-1}(x)\) in terms of \(a,x\). [4]
(b) If \(ff(x)=f^{-1}(x)\), find \(x\) in terms of \(a\). [2]
