In a function, each "x" can only have one "y" number. A relation can still be a function if a y-value has more than one x-value.
Answer:
11. a)
The relationship represented by the graph is a function because it passes the vertical line test (VLT). Any vertical line you pass through the graph, it only "hits" one spot on the graph. For a relation to be a function, each x-value can only have one y-value. This means no hour can have two different amounts of bacteria.
b)
If there were the same number of bacteria for two consecutive hours, the graph would still represent a function. In this case, two values for "y" will have more than one value for "x". Although, each x-value still only has one y-value, so it's still a function.