Final answer:
To find the roots of the cubic polynomial 2x³ + x² - 16x - 15 = 0, one must use methods such as factoring, synthetic division, or the Rational Root Theorem, not the quadratic formula.
Step-by-step explanation:
Finding the roots of the polynomial 2x³ + x² - 16x - 15 = 0 involves solving for the values of x that satisfy the equation. This can typically be done using factoring, synthetic division, or by applying the Rational Root Theorem to guess possible rational roots and test them. However, if the polynomial were a quadratic equation of the form ax² + bx + c = 0, the roots could be easily found using the quadratic formula, √(b² - 4ac) / 2a. Nonetheless, the given polynomial is cubic, not quadratic, so a different approach is needed. One way to start might be to look for any obvious rational roots by applying the p/q rule, where p is a factor of the constant term and q is a factor of the leading coefficient. For more complex cases, numerical methods or algebraic manipulations could be used to approximate or find the exact roots.