I have to solve a algebraic expression using a quadratic formula.

This is it:

X2 - 2X - 6 = 0

I used the quadratic formula on your site here to help me. So...

a=1, b=-2, c=-6

X= +3 ± |4 - 4 * 1 - (-6)

-------------------------

2 * 1

= 3 ± |0

----------

2

= 3 ± 0

--------

2

.........and I got 1.5

But when i put it to the equation

*X2 - 2X - 6 = 0*I get 0.75, it should be 0 right?

Does anybody know where i possible went wrong?