(i)[2]
Express $2x^2 - 12x + 7$ in the form $2(x + a)^2 + b$, taking $a$ and $b$ to be constants.
(ii)[1]
State the range attained by $f$.
(iii)[1]
The function $g$ is specified by $g : x \mapsto 2x^2 - 12x + 7$ for $x \leq k$. State the largest value of $k$ for which $g$ has an inverse.
(iv)[3]
Given that $g$ has an inverse, find an explicit expression for $g^{-1}(x)$.