Each time x increases by 2 (eg: from x = -3 to x = -1), the value of y increases by 7 (eg: y = 9.5 to y = 16.5)
Change in y = 7
change in x = 2
Slope = (change in y)/(change in x) = 7/2 = 3.5
This all means that we have a linear equation
10/7,8 ...................
-30 is the answer for your question
Well to begin, you'll need a graph but you have to do:
y2-y1
---------
x2-x1
(Which is the average rate of change formula.)
In order to find your "y" you look for your x on the graph the move either direction until you touch the graph. Hope this helps.. :)
