Babylonian Problem - circa 1800 BC

An area, A, consisting of the sum of two squares is 1000. The side of one square is 10 less than 2/3 of the side of the other square. What are the sides of the squares?

a^2+b^2=1000

a=2/3 b - 10

so square the second equation, put it in the first equation, and solve for b first.