Abreeder of horses wants to fence two adjacent rectangle grazing areas along a river with 600 meters of fence.

- write an expression for the total are of the land in terms of the width of the rectangle

Each person in an it department of 25 people works on at least one of 3 major projects: system security, program implementation, platform development. 10 people work on system security, 13 work on program implementation, and 12 work on platform development. 4 people work on system security and platform development, 5 people work on program implementation and platform development, and 2 people work on all three projects. how many people work on system security and program implementation?