Question

A student is given the problem: x^3+7x+9. Which of the following statements is false? A. Completing the square cannot be used to solve the given equation. B. Completing the square can only be used to solve a quadratic equation. C. Completing the square can be used to solve the given equation. D. Completing the square cannot be used because of the x^3 term.

Answer 1

False: C. Completing the square can be used to solve the given equation.

Explanation:

First of all, no equation is given. Any answer that suggests a way of finding solutions to the given equation will be false.

The statement of B is debatable. The method of completing the square is most often used for quadratics, but might reasonably be applied in any situation where a perfect square can be created by regrouping the terms.

Statements A and D essentially say the same thing. Both are true. That fact makes statement C false. Statement C is the one you're looking for.