To solve the equation \( q(q + 4) = 0 \), we can use the property that if a product of two factors equals zero, then at least one of the factors must be equal to zero.
This gives us two equations to consider:
- \( q = 0 \)
- \( q + 4 = 0 \)
Now, solving the second equation:
\[ q + 4 = 0 \] \[ q = -4 \]
Thus, the solutions to the equation \( q(q + 4) = 0 \) are:
\[ q = 0 \quad \text{or} \quad q = -4 \]
So, the final answers are:
\[ q = 0 \quad \text{or} \quad q = -4 \]