#### Answer

positive and negative 12

#### Work Step by Step

The answer is positive and negative 12 because the problem is $a^{2} = 144$. To find a, we would square root both sides of the equation and get a= positive and negative 12. Both the square of positive and negative 12 equals 144 because 12 * 12 = 144 and (-12) * (-12) = 144 as well.