Icant remember this its not a test but i have more questions can someone pleas with a simple way of working it

Assume that your equation is such form Now you must find what m and n are. Just try given points that are (x,y) = (0,-2), (1,4), (2,10), (3,16), (4,22) and (5,28) Only two of them enough to find what m and n are. I picked (0,-2), (1,4) and put them in equation. Let me show you.

For (0,-2) : then I have Now I must find m=?

I used (1,4) then (I know what n is) Hence I have m=6

Therefore your equation is so ?=6 in picture.

2160ft^3 i think you could use a formala to you out with this in the future