The start of this graph has the coordinate (-4,-1)
and the end of this graph has the coordinates (2,1)
From the star to the end, the graph is continued between x = -4 and x = 2, then the DOMAIN where this graph continues (is not interrupted) is between:
x = -4 and x = 2. In short it's continued in the interval [ - 4 and +2] which could be written -4 ≤ x ≤2
So the DOMAIN is for x having all values in the interval -4 ≤ x ≤2
Hope it helped you