(2x-1)^2=(√2-1)^2
(2x-1)^2 - (√2-1)^2 = 0
平方差公式分解[(2x-1)- (√2-1) ] [(2x-1)+ (√2-1) ] =0
所以2x-1 = √2-1 或2x-1 = -(√2-1)
解得 x= - √2 / 2 + 1 或 x = √2 / 2