^{x2}-1=2x

x

^{2}- 1 = 2xFirst, put the equation into standard form (ax

^{2}+bx+c=0):x

^{2}- 2x -1 = 0This equation does not factor readily, so let's use the Quadratic Formula:

x = (-b/2a) ± (1/2a)(b

^{2}- 4ac)^{1/2}For your problem, a=1, b=-2, and c=-1:

x = (2/2) ± (1/2)[(-2)

^{2}- 4(1)(-1)]^{1/2}x = 1 ± (1/2)[4 + 4]

^{1/2}x = 1 ± (1/2)(√8) = 1 ± (1/2)(2√2)

x = 1+√2 and 1-√2

## Comments