let x = {p ∈ z | p = 5a + 2 for some integer a}, y = {m ∈ z | m = 4b + 3 for some integer
b}, and z = {n ∈ z | n = 4c − 1 for some integer c}.
is x ⊆ y ? (2pts)
justify your answers carefully. (in other words, provide a proof if the statement is true or a disproof if the statement is false.) (8 pts)