Let X and y be positive real numbers, and 12 + X + 12 + y = 13, then the minimum value of XY is______ .

Let X and y be positive real numbers, and 12 + X + 12 + y = 13, then the minimum value of XY is______ .

∵ X and y are positive real numbers, and 12 + X + 12 + y = 13. Further, we simplify xy-x-y-8 = 0. X + y = XY-8 ≥ 2XY, let t = XY, t2-2t-8 ≥ 0, ∵ t ≤ - 2 (rounding off), or t ≥ 4, that is, XY ≥ 4, we can get the minimum value of & nbsp; XY ≥ 16, ∵ XY is 16