Question 1006216
{{{graph(300,300,-18,10,-10,10,(x-10)/(x+6))}}}
Imagine any horizontal lines you want, through the graph.  More than one intersection anywhere?


Also, for two different variables, a and b,
{{{(a-10)/(a+6)=(b-10)/(b+6)}}}
and if you try solving this to look at how a and b relate to each other,
...
..
you will find  {{{b=a}}}  or {{{a=b}}}.
This means any a or b is the same value or same number.  This looks like one-to-one.