Question 1008608

{{{h(x)=-8x+360}}}

to reach the ground, {{{h(x)}}} must be ={{{0}}}

{{{0=-8x+360}}}

{{{8x=360}}}

{{{x=360/8}}}

{{{x=45}}}=> x-intercept and the time it took the hot air balloon to reach the ground was {{{45}}} seconds

domain  should be {{{0<x<infinity}}}, but you have restricted range to {{{360}}} 
you might go with
{{{0<x<65}}} or {{{0<x<70}}}