Part A: This graph does equal a linear function because it is a straight line, passing through each of the points. Also because x (1) and y (4) increase at the same amount.
Part B:
Example of a linear function: (1, 2) (2, 4) (3, 6). This is a linear function because every time x increases by 1, y increases by 2. They both increase by the same amount. Another reason it's a linear function is because when you put these point on a graph it is a straight line.
Example of a non- linear function: (2, 4) (5, 10) (7, 11). This is a non- linear function because x and y are increasing at different amounts each time. It would also not be straight on a graph.
Hope this helps!!