To reflect the function \( y = (x + 1)^2 \) across the y-axis, we need to replace \( x \) with \( -x \) in the equation.
Starting with the original function:
\[ y = (x + 1)^2 \]
Reflecting across the y-axis, we substitute \( -x \) for \( x \):
\[ y = (-x + 1)^2 \]
This can be simplified:
\[ y = (1 - x)^2 \]
The transformed function that reflects across the y-axis is:
\[ y = (1 - x)^2 \]
So the equation of the transformed function is:
\[ y = (1 - x)^2 \]