First, add the fractions on top. Find common denominators:
Multiply out the second fraction on top.
Add the tops on the top.
The top simplifies to
We are now ready to invert and multiply.
Cancel, and it simplifies to
Note that we could go straight from
to the answer. Cancel out the things that would cancel if you inverted and multiplied.
and the only thing that is left is the B in the top.
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