Answer :

Answer:

a = -2 z^-3 c^6

Step-by-step explanation:

equations are given as

a = 2b^3              .....1  and

b = -1/ z c^-2        .....2

put the value of b in eq 1

a = 2(-1/z c^-2)^3

a = 2(-1/z^3 c^-6)

or  a = -2 z^-3 c^6