Provide an appropriate response.Why does a linear function always have an inverse?

Question

What will be an ideal response?

Answer 1

Answers will vary. One possibility: actually, a linear function does not always have an inverse. Any horizontal line,  is a linear function; but it will obviously fail the horizontal line test (since the horizontal line  will intersect the graph an infinite number of times). However, every other linear function always passes the horizontal line test. Therefore, any such linear function is one-to-one and thus has an inverse.