(x-4)² - 6 = (2+x)²
(x-4)(x-4) - 6 = (2+x)(2+x)
x² - 8x + 16 - 6 = x² + 4x + 4
x² - 8x + 10 = x² + 4x + 4
-8x + 10 = 4x + 4
-8x - 4x = 4 - 10
-12x = -6
x = -6 / -12
x = 0.5

Ответ: x = 0.5