Question

-x2 + x-1=0

Answer 1

-x^2 + x-1=0 divide by (-)  

 x^2-x+1=0  

 x=1/2(+-) root of (1/2)^2-1  

 x=1/2(+-) root of (1/4)-1  
  
x=1/2(+-) root of (1/4)-1   

x=1/2(+-) root of (1/4)-((4*1)/4)   

x=1/2(+-) root of (-3/4)   

 which has not answers, because we can  not take a root of negatives numbers

Answer 2

Ax² + bx + c = 0
-x² + x - 1= 0
x = -b +/- √b² - 4ac
                2a
x = -1 +/- √1² - 4(-1)(-1)
                  2(-1)
x = -1 +/- √1 - 4
             -2
x = -1 +/- √-3
            -2
x = -1 +/- (-1.732050808)
                  -2
x = -1 - 1.732050808        x = -1 + 1.732050808
                 -2                                      -2
x = -2.732050808             x = 0.732050808
              -2                                     -2
x = 1.366025404              x = 0.366025404