1．The function f is given by $$\mathrm { f } ( x ) = x ^ { 2 } - 4 x + 9 \quad x \in \mathbb { R } , x \geqslant 3$$ （a）Find the range of f ． The function g is given by $$\operatorname { g } ( x ) = \frac { 10 } { x + 1 } \quad x \in \mathbb { R } , x \geqslant 4$$ （b）Find an expression for \(\operatorname { gf } ( x )\) ．
（c）Find the domain and range of gf．