Question: solve for infinity

A colleague just asked me what Maple would do if asked to solve an equation in which the right hand side is infinity. I didn't really know what it would do, so we did some tests:
f := (x-1)/expand((x-1)*(x+1)*(x-2)):
solve( f=infinity, x );
                                    1, -1
solve( 1/f=0, x );
                                    2, -1
solve( denom(f)=0, x );
                                  1, 2, -1
I could not explain the response to the first solve command. Can you? Thanks in advance, Doug
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