solution: We plug in $x = 4$: \begin{align*}
  3(4) + 2y &= 12\\
  12 + 2y &= 12\\
  y &= 0.
  \end{align*}
  
  Therefore, $b = \boxed{0}$.
prompt.content: <|im_start|>system
  You are a helpful assistant.<|im_end|>
  <|im_start|>user
  The point $(a, b)$ lies on the line with the equation $3x + 2y = 12.$ When $a = 4$, what is the value of $b$?
  Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
  <|im_start|>assistant
  
prompt.role: user
extra_info.answer: 0
extra_info.question: The point $(a, b)$ lies on the line with the equation $3x + 2y = 12.$ When $a = 4$, what is the value of $b$?
extra_info.split: test