math
posted by LA .
Use a graph to determine whether the given function is continuous on its domain. HINT [See Example 1.]
f(x) =
x + 7 if x < 0
2x − 5 if x ≥ 0
1
continuous discontinuous
If it is not continuous on its domain, list the points of discontinuity. (If there is no such point, enter NONE.)
x = 2

This is very simple and quick to graph.
Have you tried to graph these?
What don't you understand? 
In google type: "function graphs online"
When you see list buf results click on:
rechneronline.de/functiongraphs/
When page be open in blue rectacangle
type: x+7
in grey rectacangle click: 2*x5
In Display properties set:
Range xaxis 20 to 20
and
Range yaxis 20 to 20
Then click option Draw