Question 167373

 (a +4 )^2 - 2(a + 4 ) +1 =0  

consider a + 4 = x

 i.e .  x^2 - 2x +1 =0

          x^2 -1x -1x +1 = 0 
            x ( x - 1 ) - 1 ( x -1) = 0
                  (x -1) (x -1) =0
                     x = 1

                 but x = a + 4 
                  a + 4 = 1
                     a = 1 - 4 
                        = 1 + -4 = -3