D. is not a function because it has two y values for a single x value. This is said to fail the vertical line test for functions. There must be only one single unique output for each unique input. Otherwise it is not a function...
Answer:
milligram would be 3.2e+7 or if not 3.2
Y=-1/2x-3
You can rewrite the equation “y=mx+b” and fill in what you know. So your equation would look like y=-1/2x+b when filling in what you know. Now you can take the (x,y) coordinates that you were given and plug them into the equation and solve for b. So now it would be -5=-1/2(4)+b