Let E and f be on the edge BC and CD of rectangular ABCD respectively, and the areas of △ Abe, △ ECF and △ FDA are a, B and C respectively. Find the area s of △ AEF

Let E and f be on the edge BC and CD of rectangular ABCD respectively, and the areas of △ Abe, △ ECF and △ FDA are a, B and C respectively. Find the area s of △ AEF

Let AB = x1, be = X2, EC = X3, CF = x4, then FD = x1-x4, ad = x2 + X3. From the meaning of the title, we get x1 ·x2 = 2A, x3 ·x4 = 2B, (x1-x4) × (x2 + x3) = 2c, that is, x1 ·x3-x2 ·x4 = 2 (B + C-A), and then substitute x1x2x3x4 = 4AB into x2x4 = x1x3-2 (B + C-A) to get the univariate quadratic equation about x1x3