Which expression represents a quadratic equation?

Which expression represents a quadratic equation?

• A. x^3 - x + 2
• B. x^2 - x + 2
• C. x^2 + x
• D. 2x

Answer: (B)

A quadratic expression has the highest power of the variable equal to 2. Among the options, the one with x^2 as the highest term and a nonzero coefficient is x^2 - x + 2, which fits the form ax^2 + bx + c with a ≠ 0. The other options either involve a higher power (x^3), or are linear (2x), or, even though x^2 + x has the same highest power, it lacks the constant term and is less clearly presented in the standard three-term form. Therefore, x^2 - x + 2 is the best representation of a quadratic expression.

A quadratic expression has the highest power of the variable equal to 2. Among the options, the one with x^2 as the highest term and a nonzero coefficient is x^2 - x + 2, which fits the form ax^2 + bx + c with a ≠ 0. The other options either involve a higher power (x^3), or are linear (2x), or, even though x^2 + x has the same highest power, it lacks the constant term and is less clearly presented in the standard three-term form. Therefore, x^2 - x + 2 is the best representation of a quadratic expression.