The given equation is
s(11 - s) = 24
We can expand the bracket by multiplying each term inside the bracket by the term outside.
It becomes
11s - s^2 = 24
- s^2 + 11s - 24 = 0
Multiplying through by - 1, it becomes
s^2 - 11s + 24 = 0
We would factorise by finding two numbers whose sum or difference is - 11s and whose product is 24s^2. The numbers are - 8s and - 3s
Therefore, the equation becomes
s^2 - 8s - 3s + 24 = 0
s(s - 8) - 3(s - 8) = 0
(s - 8)(