This is why it's important to write the problem out with numbers, symbols, and parentheses when you post.
Does "8 to the power of x plus 1" mean 8^(x+1) or (8^x) + 1 ?
Does "4 to the power of 3x minus 1" mean 4^(3x-1) or (4^(3x)) - 1 ?
There's at least 4 different versions of this problem, depending on which of the above choices is made.
Here's one version:
8^(x+1) * 2^(2x) = 4^(3x-1)
(2^3)^(x+1) * 2^(2x) = (2^2)^(3x-1)
2^(3x+3) * 2^(2x) = 2^(6x-2)
2^(3x+3+2x) = 2^(6x-2)
2^(5x + 3) = 2^(6x-2)
5x + 3 = 6x - 2
-x + 3 = -2
-x = -5
x = 5