Always state the problem in full, we can only answer what's put in front of us
Start by expanding the brackets:here is the main problem :
then i tried to simplify it as i wrote in the 1st post
the solution set is {5}
Multiplying by each term in the second bracket:
Multiplying by each term in the second bracket
The expanded form is the sum of these:
Can you go from there? I expect a few terms will cancel