Respuesta :

Answer:

x = 80 b^12

Step-by-step explanation:

given as

x =(5a^4)          ....1                         and a =(2b^3)         ......2

now if we put the value of a in eq 1, then we can write x in terms of b

therefore x= (5(2b^3)^4)

                 = (5(2^4×b^12))

                 = (5(16× b^12))

                 = 80 b^12