Which of the following is an example of a polynomial?

A polynomial is defined as an expression made up of variables raised to non-negative integer powers, with coefficients that are also real numbers. In the context of the provided choices, the expression 3x^2 + 2x - 1 meets all the criteria for being a polynomial:

1. Non-negative integer powers: The terms 3x^2, 2x, and -1 consist of x raised to the power of 2 (which is non-negative and an integer), x raised to the power of 1 (also non-negative and an integer), and a constant term -1 (which can be considered as x raised to the power of 0).

2. Real coefficients: The coefficients (3, 2, and -1) are all real numbers.

In contrast, the other expressions do not qualify as polynomials:

• The expression 1/x + 4 includes a term (1/x) which can be rewritten as x^-1, indicating a negative exponent, which disqualifies it from being a polynomial.

• The term Sqrt(x) + 2 involves the square root of x, which can be expressed as x^(1/2). Since 1/2 is