\( 4 \times \) Which equation has both 5 and -5 as possible values of \( y \) ?

To find an equation that has both 5 and -5 as possible values of \( y \), we can start by constructing a simple quadratic equation. Consider the equation \( y^2 - 25 = 0 \). This can be factored into \( (y - 5)(y + 5) = 0 \). Setting each factor to zero gives us the solutions \( y = 5 \) and \( y = -5 \), making this equation a perfect fit! Moreover, quadratic equations represent parabolas that can cross the x-axis at multiple points, allowing for multiple \( y \) values—as seen with our specific equation. It's fascinating how parabolas can represent a wide range of situations in the real world, from the paths of projectiles to the shapes of satellite dishes!