The only possible way to answer this question is by making sure you know what a "polynomial" is. If you do a google search for "polynomial" or consult Wikipedia you find something like "A polynomial is an expression in one or more variables involving only addition, subtraction, or multiplication." Of course, repeated multipliction can give positive integer powers so you can include those. You cannot have fractional powers (roots) or negative powers (fractions) or anything more complicated.
Now part of the problem here is that what you have written is ambiguous. For example, -3x^2- 1/2x- 9.1 could be interpreted as -3x^2- (1/2)x- 9.1 or as -3x^2- 1/(2x)- 9.1. One is a polynomial and the other is not.
