With the given information in the diagram which is not true

take any 2 points, so we'll us (2,14) and (4,28) 16,32

then do y2-y1/x2-x1

so 28-14=14
4-2×2
so then do rise(y) over run(x)
so the slope is 14/2 which simplifies to 7
so the rate of change is
y=7x

 last year if 2 bushels cost $10 then 10/2 = $5 per bushel

 so this year the bushels cost $7

7-5 = $2 increase this year