System 1:Let , , , , then System 2: Multiply the 2nd equation by 3 Add the two equations: Factor the left side: Take cube roots of both sides: Eq. 1 Factor the left side of the 1st equation in system 2 Use Eq. 1 to substitute 9 for (x+y) , reduce 183/9 to 61/3 Eq. 2 Square both sides of Eq. 1: Eq. 3 Multiply Eq. 2 by -1 and add Eq. 3 Substitute for xy in in Eq. 2 Since x²=a and y²=b, Edwin