1/a+1/b=1/200,
(a+b)/ab=1/200, (a,b≠0)
a+b=ab/200,
200a+200b=ab,
200b=ab-200a, a=200b/(b-200), conversely b=200a/(a-200). (a,b≠200)
When a=1, b=-200/199=-1.005, conversely when b=1, a=-1.005.
When a=400, b=80000/200=400, conversely when b=400, a=400.
When a=100, b=20000/(-100)=-200, conversely when b=100, a=-200.
When the equation is graphed, there are asymptotes at a,b=200, so there are two curves containing the ordered pairs.
When a is very large, b approaches 200 and vice versa.
When a is small, b approaches -a, and vice versa, but (0,0) is not an ordered pair.