(i)[2]
Write $x^2 - 4x + 8$ in the format $(x - a)^2 + b$.
(ii)[3]
Therefore determine the set of $x$ values for which $f(x) < 9$, and present the answer exactly.
Mathematics 9709 · AS & A Level · Quadratics
Quadratics — practice question
The function $f$ is given by $f(x) = x^2 - 4x + 8$ for $x \in \mathbb{R}$.