(2х)в квадрате -18= 0
4x^2 - 18 = 0 2x^2 - 9 = 0 2x^2 = 9 x^2 = 9/2 x = ± 3/√2
(2x)²-18=0 4x²=18 x²=18/4 x=+- √ 18/√4 x= +- √18 / 2 = +- √9*√2 /2 = +- 3√2/2