Avan and a truck both drove from town a to town b. the distance
between town a and town b is 200 miles. the van left town a 1 1/2 hours
earlier than the truck. the van reached town b 2 1/2 hours before the truck.
the truck traveled at an average speed of 40 miles per hour. what was the
average speed of the van?

to plot points   for x just start at the origin (middle) and go to the left however many times it say(if the number is a positive) if the number is a negative then go right however many times it says if it is 0 go nowhere

now keep you pencil there and go up however many times it says on y(if it is positive) if it is negative then go down however many times it says. if it says 0 go nowhere.

you have just plotted a point! now when you finish plotting all of them connect them with a ruler

plot each point as (-3, 7), (0,4), (3,1), (8,-4)   in the parenthesis on the left of the comma is x and the right is y.

yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value