Question

(2x+3) elevado a la 2=81

Answer 1

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