First, add #color(red)(33)# to each side of the equation to isolate the #x# term while keeping the equation balanced:

#3x^2 - 33 + color(red)(33) = 0 + color(red)(33)#

#3x^2 - 0 = 33#

#3x^2 = 33#

Next, divide each side of the equation by #color(red)(3)# to isolate the #x^2# while keeping the equation balanced:

#(3x^2)/color(red)(3) = 33/color(red)(3)#

#(color(red)(cancel(color(black)(3)))x^2)/cancel(color(red)(3)) = 11#

#x^2 = 11#

Now, take the square root of each side of the equation to solve for #x# while keeping the equation balanced. Remember, the square root of a number produces a positive and negative result:

#sqrt(x^2) = +-sqrt(11)#

#x = +-sqrt(11)#

Or

#x = +-3.317# rounded to the nearest thousandth.