12
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Given $\|\mathbf{v}\| = 4,$ find $\|-3 \mathbf{v}\|.$
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
12
Given $\|\mathbf{v}\| = 4,$ find $\|-3 \mathbf{v}\|.$
train