I cant draw to show it on the number line
to get the equation of a line, we simply need two points, say for the Red one ... notice in the graph the lines passes through (0,2) and (-1,6), so let's use those

now, for the Blue one, say let's use hmmm it passes through (0,2) and (1.6)

Since the hundred place is the 4 and the tens place is higher than 5 ( it is 7) to round to the hundreds place it would be 9500
By using numbers and solving it how your teacher teached you lol XD