The circle on the far left is the sum of 4x + 3y and 2x - y so the answer is 4x + 3y + 2x - y = 6x + 2y. The circle on the far left is the sum of x + 4y and something. To find that "something" we can do 4x + 5y - (x + 4y) = 3x + y which is the value of the bottom right rectangle. This means that the value of the bottom circle is 2x - y + 3x + y = 5x.
