(Х-5)^2=5х^2-(2х-1)(2х+1)
X^2 - 10x + 25 = 5x^2 - (4x^2 - 1) x^2 - 10x + 25 = 5x^2 - 4x^2 + 1 x^2 - 10x + 25 = x^2 + 1 x^2 - 10x + 25 - x^2 - 1 = 0 - 10x + 25 - 1 = 0 - 10x + 24 = 0 - 10x = - 24 10x = 24 x = 2,4