What is the least numbers
when subtracted from
308 will make it divisible by 6

For finding the values, we look at the x - value given. Then we move to where it is on the graph and find its y  value.

In part A, when x = -4, the y value looks to be between -3 and -4. Let's put it in the middle and estimate it at -3.5

In part B, when x = 1, the process is similar.  Go to x = 1, then go to the graph, then go to the y value.  That looks to be at y = -3.

In part C, when x = 4, there are three values that work. We are actually answering part D at this point because we can tell this graph is NOT a function of x. When you have an x -value that goes into the function, you have to get EXACTLY ONE thing that comes out.  I bolded "EXACTLY ONE" because those words make the definition work. Two or more, not a function. One, it's a function. None, and it's not in the domain at all.  There are three values of y that work, and they are - from top down, 3.5, 0, -2.5.

We answered Part D when observing part C. It's NOT a function because there is not EXACTLY ONE value of y for an x.

And finally, because it's not a function - finding the domain and range is a waste of time. You can't find the domain of something that's not a function - you need a function to have a domain.

Hope that helps.