Answer:
a. a(b)c
b. a(a(b)c)c
d. a(a(a(a)c)c)c
Step-by-step explanation:
We are given the following in the question:
a. a(b)c
It is given b belongs to W.
b. a(a(b)c)c
c. a(abc)c
a(abc)c does not belong to W because we cannot find x in W such that a(abc)c belongs to W.
d. a(a(a(a)c)c)c
e. a(aacc)c
a(aacc)c does not belong to W because we cannot find x in W such that a(aacc)c belongs to W.