2. The quadratic function \( y=9-x^{2}+4 x \) written in standard form would be: \( \begin{array}{ll}\text { (1) } y=-x^{2}+4 x+9 & \text { (3) } y=x^{2}-4 x+9 \\ \text { (2) } y=x^{2}-9 x+4 & \text { (4) } y=-x^{2}-4 x+9\end{array} \)

To express the quadratic function \( y = 9 - x^{2} + 4x \) in standard form, we rearrange it to combine like terms. This leads us to \( y = -x^{2} + 4x + 9 \). So, the standard form is option (1): \( y = -x^{2} + 4x + 9 \). Fun fact: Quadratic functions like this one can describe various real-life situations, including the path of a projectile! When you throw a ball, its height can be modeled using a quadratic equation, showcasing how math and physics intertwine in everyday life.