Even though factoring is an acceptable method for solving, the square root method allows you to solve using the inverse relationship between taking the square root and squaring. The square root property states that if x2 = N and N is not negative, then x = or x = -.

When solving an equation, we are not sure if it is the positive or negative root or both that are solutions. Therefore, we must consider both roots when solving. We use the notation ± , read as "plus or minus."
Determine the solution set of x2 - 80 = 0.

{± }
{±4 }
{±2 }Determine the solution set of (x + 2)2 = 36.

{4, -6}
{4, -8}
{6, -8}