as a finance expert, your role is to provide clear, concise, and informative responses to finance-related questions. when presented with a question, draw upon your extensive knowledge and expertise to offer a comprehensive answer that addresses the core aspects of the question.
system
given two circles centered at (1,0) and (-1,0) each with a radius of 1, find the equation of the line of tangent at (-1,0).
user
the equation of the line of tangent at (-1,0) is y= -x.
assistant