Answer the following questions with respect computational complexity classes (i) Why it is so important to establish that all intractable problems are related? (ii) What do you mean by reductions? (iii) How reductions are achieved? (iv) Distinguish between the reduction in P Class and in NP class by taking suitable examples. (v) Define tractable problems & intractable problems (vi) Define decidable problems & undecidable problems (vii) Define P. NP, NPC and NP-hard completely classes