Determine whether the following are polynomials or not:2x^2 + 7x+ 1,1/(x^3 + 2),6,8x – 1,sqrt(2x + 5).

Polynomials
Determine whether the following are polynomials or not: $$2x^2 + 7x+ 1, 1/(x^3 + 2), 6, 8x – 1, \sqrt{2x + 5)}$$
$$2x^2 + 7x+ 1$$ - polynomial $$1/(x^3 + 2)$$– not polynomial 6 – polynomial 8x – 1 - polynomial $$\sqrt{2x + 5}$$ - not polynomial