one way: expand the left hand side:

so we have:

now equate the coefficients of like powers of x.

from this we see:

..............(1)

...............(2)

.........................(3)

since you know C and D, solving for A and B should be easy from this system ...oh wait, we still have a clue missing

there might be some virtue in doing

so the partial fractions are:

if you desire you can work on the second fraction a bit more to see if you can get partial fractions from it