Determine if a Polynomial -5st^5 square root of 6+8t^5-7s^4 square root of t

$- 5 s t^{5} \sqrt{6} + 8 t^{5} - 7 s^{4} \sqrt{t}$

A polynomial is a combination of terms separated using $+$ or $-$ signs. Polynomials cannot contain any of the following:

1. Variables raised to a negative or fractional exponent. ( $2 x^{- 2}$ , $x^{\frac{1}{2}}$ , $\dots$ ).

2. Variables in the denominator. ( $\frac{1}{x}$ , $\frac{1}{x^{2}}$ , $\dots$ ).

3. Variables under a radical. ( $\sqrt{x}$ , $\sqrt[3]{x}$ , $\dots$ ).

4. Special features. (trig functions, absolute values, logarithms, $\dots$ ).

Determine if the expression breaks any of the rules.

Breaks rule $3$

Determine if the expression is a polynomial.

Not a polynomial