(a)[4]
Write $ff(x)$ and $f^{-1}(x)$ in terms of $a$ and $x$.
(b)[2]
Since $ff(x) = f^{-1}(x)$, determine $x$ in terms of $a$.
Mathematics 9709 · AS & A Level · Functions
Functions — practice question
For $x \in \mathbb{R}$, the function $f$ is defined by $f: x \mapsto a - 2x$, where $a$ is a constant.