Respuestas

2013-11-05T00:00:42+01:00
4x^2 + 12 x +9 =81

4x^2 + 12x -72 = 0

x^2 + 3x -18 = 0

     -3±√(3²+4 . 18
x = -----------------                     
            2
      x1 = 3
      x2 = -6