3x – 2 = A(x + 1)(x + 3) + B(x + 3) + C(x + 1)²

Put x = – 1

– 3 – 2 = A × 0 + B × ( – 1 + 3) + C × 0

– 5 = 2B

Put x = – 3

– 9 – 2 = C × ( – 2)( – 2)

– 11 = 4C

Equating coefficients of constants

– 2 = 3A + 3B + C

Thus,