Solving by Square Roots

No First-Degree Term

If the quadratic has no linear, or first-degree term (i.e. b = 0), then it can be solved by isolating the x2 and taking square roots of both sides:

  • You need both the positive and negative roots because , so x could be either positive or negative.
  • This is only going to give a real solution if either a or c is negative (but not both)