First, let us divide by as usual numbers. We need to multiply by , to cancel . Subtracting , obtain remainder , so no further reduction is possible.
Hence, , from where .
The remainder has degree of polynomial in the numerator smaller, than degree of the denominator. Hence, we can decompose it into partial fractions: , from where equating the coefficients next to powers of in the left and right hand sides of previous equation, obtain linear system, from where .
Therefore, , and finally