To find the function \( g(x) \) based on the rule \( rx \)-axis, we need to reflect the function \( f(x) = -2x + 1 \) across the x-axis.
To reflect a function \( f(x) \) across the x-axis, you multiply the function by -1. Therefore, the reflection will be:
\[ g(x) = -f(x) = -(-2x + 1) = 2x - 1 \]
So, the correct function is:
\[ g(x) = 2x - 1 \]
Hence, the response is:
g(x) = 2x - 1