Find(a) [Z24 : ⟨8⟩] and the number of right cosets of ⟨8⟩ in Z24.(b) [U(8) : ⟨3⟩] and the number of right cosets of ⟨3⟩ in U(8).(c) [Z : 4Z] and the number of right cosets of 4Z in Z

8. Is the expression 16 - 6x18 a polynomial. If it is not, what rules it out? yes no if no, what rules it out?_ 9. Is the expression x-'(x– 4) – x²(1 – x³) a polynomial. If not, what rules it out? yes no if no, what rules it out?