1. The problem asks if number 3 is also solved using the quadratic formula. 2. The quadratic formula is used to solve quadratic equations of the form $$ax^2 + bx + c = 0$$. 3. The formula is $$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$. 4. To determine if number 3 uses this formula, check if the equation is quadratic (degree 2). 5. If number 3 is a quadratic equation, then yes, the quadratic formula applies. 6. If it is not quadratic, then the quadratic formula does not apply. 7. Without the exact equation from number 3, we cannot definitively say, but the quadratic formula is only for quadratic equations.