The graph represents a linear function that passes through the origin.
Step-by-step explanation:
Proportional functions can be represented by , where is some constant. They form a straight line that always pass through the origin (0,0). We can see all these characteristics in the graph, thus the graph is proportional.
One half of a number represents the phrase "1/2a" (in this case the variable/number is 'a'". Then because it says "nineteen less than", that means you subtract 19 from one half of the variable.