問3條F.4既數學..好急

1. (x + x + 1 + x + 2)^2 - [x^2 + (x + 1)^2 + (x + 2)^2] = 94
(3x + 3)^2 - x^2 - (x + 1)^2 - (x + 2)^2 = 94
9x^2 + 18x + 9 - x^2 - x^2 - 2x - 1 - x^2 - 4x - 4 = 94
6x^2 +12x - 90 = 0
x^2 + 2x - 15 = 0
(x + 5)(x - 3) = 0
x = -5 or x = 3
2. x^2 + (x - 2)^2 = 10^2
x^2 + x^2 - 4x + 4 = 100
2x^2 - 4x - 96 = 0
x^2 - 2x - 48 = 0
(x - 8)(x + 6) = 0
x = 8 or x = -6
3. x^2 + (80 - x)^2 = 272*16
x^2 + 6400 - 160x + x^2 = 4352
2x^2 - 160x +2048 = 0
x^2 - 80x + 1024 = 0
(x - 64)(x - 16) = 0
x = 64 or x = 16