solution : -
LHS == RHS // rhs and lhs
((4)^2x)/(8*4*4*4) = = (4rsqrt(2))^x // remove (-3) and place 4*4*4 in denominator
((2)^4x) == ((2)^(5x/2)) * (2^9) //bring everything in terms of 2
now solve it
2^(3x/2) == 2^9 equate the powers because the bases are same
--> x=6