First part of the question says: Solve the inequality

And after solving, the answer is

Then the next part of the question says: Hence deduce the solution to the inequality

On comparing, i replaced x in the answer to the first part with

so,

and

and

therefore,

Yes, that's right. The answer is correct but shouldn't the answer also be dealt with?

So shouldn't the right answer be... ? why is this not the answer? Please advise, thanks