This is the original fraction : $$\dfrac{8s^2}{(2s-3)^3}$$

From this I get : 

$$4As^2 - 12As + 9A + 2Bs - 3B + C = 8s^2$$

On the solution it says $4A = 8, A=2$, okay I understand this, $4As^2 = 8s^2$, and the rest is cancelled in the equation since there is only one $s^2$, but how $B=12$ and $C = 18$, I don't understand, can somebody explain please?