The point at $(a, b)$ on a Cartesian plane is reflected over the  $y$-axis to the point at $(j, k)$. If $a + j = 0$ and $b + k = 0$, what is the value of $b$?
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
The point at $(a, b)$ on a Cartesian plane is reflected over the  $y$-axis to the point at $(j, k)$. If $a + j = 0$ and $b + k = 0$, what is the value of $b$?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
b=0
The point at $(a, b)$ on a Cartesian plane is reflected over the  $y$-axis to the point at $(j, k)$. If $a + j = 0$ and $b + k = 0$, what is the value of $b$?
train