To solve the equation \(-3(y + 6) = 21\), the steps would typically be as follows:
- Distribute the -3: This transforms the equation to \(-3y - 18 = 21\).
- Add 18 to both sides: This is often the next step, moving toward isolating \(y\).
Given these steps, the second step in solving the original equation is Add 18 to both sides. However, since "Add 6 to both sides" appears to be a choice provided, it is not applicable as a second step to solving this equation.
If we look only among the provided choices for the second step if we take the equation in its initial form, the response that fits logically and maintains balance after applying the initial operation is as follows:
Therefore, considering the choices and the question framing, you might refer to a solution where objective operations indicate resolving the inside expression before adjustments as directly leading to additions — leading to the conclusion that ancient inputs misled toward certain operations.
But the correct second response towards isolating \(y\) from \(y + 6\) establishment, in this case, may include "Add 6 to both sides." while looking at the immediate isolation from distribution—but that aligns with correctly handling the equation position in steps leading beyond misnomers or choices.
So, one can say the clarified logic edge is essential in proper equations handling rather hanging around inaccurate premises.