Respuesta :

a^b(3a^b)^c = 81 a^5b

as you know 3^4 = 81

so if c= 4 then
a^b(3a^b)^4 = 81 a^5b
a^b(3^4 a^4b) = 81 a^5b
3^4 a^5b =81 a^5b
81 a^5b = 81 a^5b ..................true

so answer

4