Short answer. No it is not. A polynomial consists of more than 1 term which cannot be combined by either addition or subtraction. Actually most experts say that it must have more than 2 terms. So here is an example of a polynomial.
2x + 3y + 2z. You can't make this any simpler.
2x^3 + 3x^2 + 6x is also a polynomial. Don't get caught by saying it is not and that the terms can be combined in some way. They can't.
3x^2 + 7x^2 is not a polynomial. The x^2 are the same and therefore you can add the 3 and 7 together.
10x^2 is you answer.