Claribel C. answered 07/16/13
Chemistry, Math and Spanish Tutor
You have two different volumes:
(Pitcher) 5g-2
(Glass) g-5
To know how many gallons of water were left in the pitcher after pouring water into the glass you have to subtract the glass volume from the pitcher volume:
5g-2 - (g-5)
5g-2-g+5
Rearrange the equation (to see it clearly)
5g-g+5-2
4g+3 These are the gallons of water left in the pitcher.