Question 47909
The given quadratic equation is 
x^2 = 3x + 12 
=> x^2 - 3x - 12 = 0
here a = 1
     b = -3
     c = -12
Now according to the quadratic formula

x = [-b + (b^2 - 4ac)^(1/2)]/(2a) or [-b - (b^2 - 4ac)^(1/2)]/(2a)

  = [3 + (9 + 48)^(1/2)]/2  or  [3 - (9 + 48)^(1/2)]/2

  = [3 + (57)^(1/2)]/2  or  [3 - (57)^(1/2)]/2