A variable needs to be eliminated to solve the system of equations

You eat 8 strawberries and your friend eats 12 strawberries from a bowl. there are 20 strawberries left. which equation and solution give the original number of strawberries?

() at a farm, animals are fed bales of hay and buckets of gain.each bale of hay is in the shape of a rectangular prism.the base side lengths 2 feet and 3 feet,and the height is 5 feet. each bucket of grain is a cylinder with diameter of 3 feet. the height of the bucket is 5 feet as the height of bale. a. which is larger in area, the rectangular base of the bale or the circular base of the bucket? explain how you know b. which is larger in volume, the bale or the bucket? explain how you know

Can someone me out here and the tell me the greatest common factor