SOLUTION: x^2-x-1=0

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: x^2-x-1=0      Log On


   

Question 401097: x^2-x-1=0
Answer by jsmallt9(3758) About Me  (Show Source):
You can put this solution on YOUR website!
The equation will not factor so we must use the Quadratic Formula (or complete the square):
x+=+%28-%28-1%29+%2B-+sqrt%28%28-1%29%5E2+-+4%281%29%28-1%29%29%29%2F2%281%29
which simplifies as follows:
x+=+%28-%28-1%29+%2B-+sqrt%281+-+4%281%29%28-1%29%29%29%2F2%281%29
x+=+%28-%28-1%29+%2B-+sqrt%281+%2B4%29%29%2F2%281%29
x+=+%28-%28-1%29+%2B-+sqrt%285%29%29%2F2%281%29
x+=+%281+%2B-+sqrt%285%29%29%2F2
In long form this is:
x+=+%281+%2B+sqrt%285%29%29%2F2 or x+=+%281+-+sqrt%285%29%29%2F2