What number must be placed in the box in the equation below to produce an equation that has more than one solution: \[4x + 6 + 7x - 9 = 12x - 7 - x + \boxed{\phantom{2}}?\]
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
What number must be placed in the box in the equation below to produce an equation that has more than one solution: \[4x + 6 + 7x - 9 = 12x - 7 - x + \boxed{\phantom{2}}?\]
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
4
What number must be placed in the box in the equation below to produce an equation that has more than one solution: \[4x + 6 + 7x - 9 = 12x - 7 - x + \boxed{\phantom{2}}?\]
train