1. The problem is to find the formula used for a given mathematical or physical context. 2. Generally, formulas are expressions that relate variables to each other to solve problems or describe phenomena. 3. For example, in algebra, a common formula is the quadratic formula: $$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$ which is used to find the roots of a quadratic equation $ax^2 + bx + c = 0$. 4. In physics, formulas like Newton's second law: $$F = ma$$ relate force $F$, mass $m$, and acceleration $a$. 5. To find the formula used, identify the problem type, variables involved, and the relationship between them. 6. If you provide a specific problem or context, I can give the exact formula used for that case.