How to solve the following partial fractions expansion.?

Why to prove
A=C=E=0?

1) (As+B)/(s^2 + 1) + (Cs+D)/(s^2 + 2)

Already done.

2) 120 / ((s^2 + 1)(s^2 + 4)(s^2 + 9))

set 120 / ((s^2 + 1)(s^2 + 4)(s^2 + 9)) = (As+B)/(s^2+1)+(Cs+D)/(s^2+4)+(Es+F)/(s^2+9)
120 = (As+B)(s^2+4)(s^2+9)+(Cs+D)(s^2+1)(s^2+9)+(Es+F)(s^2+1)(s^2+4)
120 = (As+B)(s^4+13s^2+36)+(Cs+D)(s^4+10s^2+9)+(Es+F)(s^4+5s^2+4)
coff. of s^5
A+C+E=0 ...(1)
coff. of s^4
B+D+F=0 ...(2)
coff. of s^3
13A+10C+5E=0 ...(3)
coff. of s^2
13B+10D+5F=0 ...(4)
coff. of s
36A+9C+4E=0 ...(5)
coff of constant
36B+9D+4F=120 ...(6)
A=C=E=0 , B=5, D=-8, F=3

120 / ((s^2 + 1)(s^2 + 4)(s^2 + 9))
=5/(s^2+1)-8/(s^2+4)+3/(s^2+9) .....Ans

B+D+F=0
13B+10D+5F=0
13B+10D-5B-5D=0
8B+5D=0
36B+9D-4B-4D=120
32B+5D=120
B=5, D=-8, F=3