Whats the difference between the square root and the principal Square root?

Although the principal square root of a positive number is only one of its two square roots, the designation "the square root" is often used to refer to the principal square root. For positive x, the principal square root can also be written in exponent notation, as x1/2.

80x^8−68x^6+16^5−20x^4−4x^3+8x^2

hope i'm right lol