Question

. If 4 ^ (x - 1) + 4 ^ x + 4 ^ (x + 1) = 21 , then the value of x is​

Answer 1

Answer:

Step-by-step explanation:

(4^x) - (4^(x-1)) = 24

.•. (4^(x-1)) [ 4 - 1 ] = 24

.•. 4^(x-1) = 8

.•.(x-1) log4 = log8

x = 1 + (log 8 / log4 )

x = 2.5

.•. (2x) ^ x = 5^2.5 = 25√5