Getting Partial Fraction Decomposition Wrong

Question

So I have done this solution:

But it's wrong according to technology. I fail to see any error I've made in this solution, do you guys have any idea what's wrong?

Answer 1

In your fourth line you have, $As^3 +A$ and $Bs^2 + B$ but you should have $As^3 +As^2$ and $Bs^2 + Bs$

Answer 2

4th equal sign. You did not distribute the $s^2$ and so on. It should have been

$$As^3+As^2...$$