Select the expressions that are polynomials, help

Question

Select the expressions that are polynomials. There may be more than one correct answer.

1. __10x^-2+2x²-3x¹⁷-11x
2. __10x²⁴+6x²⁵-5x²²+9x³
3. __4x⁵+11x⁷-14x^`9/4` -7x¹⁸
4. __13x⁹-13x^2.5-13x¹⁵+3x⁴
5. __6x¹⁶-2x²⁰+5x⁵+`4/x^12`

Answer 1

For an expression to be a polynomial, it must contain no negative powers on variables, no radicals on variables, and no variables in the denominator.

Answer 2

Only the 2nd one....the others all have exponents which are not allowed in polynomials.