Question

1. (Ax+B)/(ax^3+bx^2+cx+d) in general formal of partial fraction
2. What are the general forms of partial fraction?

Answer 1

Not really sure what kind of reply you want.
Here is a very simple video, explaining the process
https://www.youtube.com/watch?v=HZTv4zCgEnA

Of course Sal Khan takes it to an even lower level
https://www.khanacademy.org/math/algebra-home/alg-rational-expr-eq-func/alg-partial-fraction/v/partial-fraction-expansion-1

and a bit more complicated here:
https://www.khanacademy.org/math/algebra-home/alg-rational-expr-eq-func/alg-partial-fraction/v/partial-fraction-expansion-2

or this nice one:
https://www.khanacademy.org/math/algebra-home/alg-rational-expr-eq-func/alg-partial-fraction/v/partial-fraction-expansion-3