1. The problem statement, all variables and given/known data If a, b, c, d are the positive roots of x^4 - 12x^3 - px^2 + qx + 81 = 0, then the area of the quadrilateral formed by x=a, x= -b , y = c and y = -d is: Ans: 36 2. Relevant equations Vieta, I guess. 3. The attempt at a solution I know its gonna form a rectangle with sides (a+b) and (c+d). The area would be (a+b)(c+d). The only information I have is a+b+c+d=12 and abcd=81. Somehow, I need to convert that into ac+ad+bc+bd. I have no idea how. Introducing p for ab+bc+cd+da seems useless because even that doesn't help much.