01 Which of the following expressions is a polynomial of degree 3 in \(x\)?
Answer and explanation
Correct answer: A. \(5x^3-2x+7\)
Explanation: In \(5x^3-2x+7\), the powers of \(x\) are 3, 1, and 0, so the highest power is 3. Hence it is a cubic polynomial. Option B has \(1/x=x^{-1}\), so it is not a polynomial. Exam tip: check for non-negative integer powers.