Determine whether each expression is a polynomial?

1. f(x)= 3x+ 4/3(x^3) - 7

2. g(x)= -5x^3 + x- 3/x

3. h(x)= x^3 √5 + x-3

4. k(x)=25x^2-x^3+x^5


Please help me!!

土豆2015-04-21T09:48:48Z

1 and 4 are definitely polynomials. 2 isn't, because an expression isn't a polynomial if any term has x in the denominator. For 3, it IS one if the square root of five is the coefficient of x^3. But if the radical portion is part of the exponent, it isn't a polynomial because exponents must be whole numbers.