To reflect the function \( f(x) = (x+1)^2 \) over the x-axis, we need to negate the entire function. This means we take:
\[ g(x) = -f(x) = -((x+1)^2) \]
Thus, the equation for \( g(x) \) becomes:
\[ g(x) = -(x+1)^2 \]
So the correct response is:
\[ g(x) = -(x+1)^2 \]
This matches with the option:
g(x)=−(x+1)².