1. x + y = 15 x² + y² = 63 (x+y)² = x²+2xy +y² = 225 63 +2xy = 225
2xy = 162 x y = 81 M= √(xy) = √81 = 9
2. (3a-4b)² =0 3a - 4b = 0 b = 3a/4 4a +3b = 4a+ 9a/4 = 25a/4
2a + b = 2a + 3a/4 = 11a/4 (25a/4)/(11a/4) = 25/11
3. 2x²+3y² -16√2·x + 24√3·y -208 = 0
(√2·x - 8)² + (√3·y+12)² =0 √2·x - 8 = 0 x = 8/√2 = 4√2
√3·y + 12 = 0 y = -12/√3 = - 4√3