there is a glass of 8 gallons full of water there is a glass of 5 gallons empty and a 3 gallons empty the three glasses of water have no marks, how can you equal 4 gallons and 4 gallons of water in two glasses?​

Not sure if you are saying a container with 8 gallons full of water, a container that holds 5 gallons but is empty, and a 3 gallon container that is empty? and you are asking How to fill the containers (at least 2 containers of 4 gallons each)??? If so then you pour the 4 gallons in the 5 gallon container and keep 4 in your original container. leaving the 3 gallon container empty.

maximum area = xy = (16)(32) = 512 ft2

to maximize the area of the garden, the side of the fence parallel to the side of the house should be 32 ft long, and the other two sides should both have length 16 ft.'

source

answer: y=0 if that is what u r looking for