Odpowiedź:
(2x-1)²+(2x+1)²+(2x+3)²=155
3*(2x)² + 2*1² + 12x + 9 = 155
12x² + 12x - 144 = 0
x² + x - 12 = 0
(x + 4)(x - 3) = 0
x = 3 ∨ x = -4
