1 The function f is defined by \(\mathrm { f } ( x ) = x ^ { 2 } - 4 x + 8\) for \(x \in \mathbb { R }\).
- Express \(x ^ { 2 } - 4 x + 8\) in the form \(( x - a ) ^ { 2 } + b\).
\includegraphics[max width=\textwidth, alt={}, center]{f462c036-45d3-4679-ad53-4edbf99df76d-02_67_1569_397_328} - Hence find the set of values of \(x\) for which \(\mathrm { f } ( x ) < 9\), giving your answer in exact form.