So the vertex of the above parabola (function) is
Thus coordinate of the vertex is (1,-6)
The x-intercepts , we can calculate by substituting y=0 in the given function
Thus x intercepts are `1+sqrt(6) and 1-sqrt(6).`
Now we can see above results graphically as
Where graph are intersecting x-axis. These are between 3 & 4 , and
-2 and -1.