To find the function rule for gx, we need to understand what it means to reflect a function across the x-axis.
The original function is given as f(x) = x² + 3. When we reflect a function over the x-axis, we negate the output values of the function. This means we will take f(x) and replace it with -f(x).
So, we can express the reflection gx of the original function as:
g(x) = -f(x)
This translates to:
g(x) = -(x² + 3)
Now, simplifying this gives:
g(x) = -x² – 3
Thus, the function rule for gx, the reflection of f(x) across the x-axis, is g(x) = -x² – 3.