4. The function \(f\) is defined by
$$f : x \mapsto | 2 x - 5 | , \quad x \in \mathbb { R }$$
- Sketch the graph with equation \(y = \mathrm { f } ( x )\), showing the coordinates of the points where the graph cuts or meets the axes.
- Solve \(\mathrm { f } ( x ) = 15 + x\).
The function \(g\) is defined by
$$g : x \mapsto x ^ { 2 } - 4 x + 1 , \quad x \in \mathbb { R } , \quad 0 \leqslant x \leqslant 5$$
- Find fg(2).
- Find the range of g.