To solve the equation \( -3(y + 6) = 21 \), the first step is to divide both sides by \(-3\).
After dividing both sides by \(-3\), you would then have:
\[ y + 6 = -7 \]
The second step would be to subtract \(6\) from both sides to isolate \(y\).
So, the correct response for the second step is:
Subtract 6 from both sides.