Answer:
A polynomial is writen as:
p(x) = aₙ*xⁿ + ... + a₂*x² + a₁*x¹ + a₀
So we can only have positive integer exponents of x.
the coefficients "a" can be any real number.
Let's analyze the options:
1) Here we can see a term with "√x", remember that:
√x = (x)^(1/2)
This is not an integer exponent, then this is not a polynomial.
2) This is a polynomial.
3) Here we have the term "4/x"
This can be written as:
4/x = 4*x^(-1)
Then this is not a polynomial.
4) Here we have the term "5^x"
In a polynomial we must have powers of x, not x as a power, then this is not a polynomial.
5) This is a polynomial.
6) Here we have the term " 2/x^2"
This can be written as:
2/x^2 = 2*x^(-2)
We have a negative exponent of x, then this is not a polynomial.