Because:

=>

Let
z = . The rewrite
equation as z^{2} - z -2 = 0,

Factor (z-2)(z-1) = 0 or z = 2, z = 1.

For
z = 2= or x^{2}
+ 6x -3 = 4 => x^{2} + 6x - 7 = 0 => (x+7)(x-1)
= 0 => x=-7 or x=-1

A second correct answer would be

For
z = 1= or x^{2}
+ 6x -3 = 1 => x^{2} + 6x - 4 = 0 use quadratic formula to solve ax^{2}
+ bx +c = 0. x =

x= or x=