Apartado a
$2\left( {{h^2} + 6h + 12} \right)$
Apartado b
(i) $25 \,\,\,m/s$, (ii) $24.12 \,\,\,m/s$, (iii) $24.01 \,\,\,m/s$, (iv) $24 \,\,\,m/s$
Apartado c
$24 \,\,\,m/s$