Question 420064

2^2 =4 and 256 = 2^8


 4^(3x+5)=1/256.

=> 2^(6x+10) = 2^(-8)

here value at base are equals, compare exponent..

6x+10 = -8

=> 6x  = -18 

=> x = -18/6 = -3

so, x = -3