the principal square root is the positive root (y2 means y^2, right? so if so then continue) that means that y^2=5 and y is positive square root means find x times x =the original number and x is the square root you can have an example 4 square root of 4 is 2 or -2 because 2 times 2=4 and -2 times -2=4 the principal one is the positive one
