THE MAIN DIFFERENCE BETWEEN (i) & (ii) :- SIGNS ARE DIFFERENT. In (i) , there's a + sign in between (8x - 3) & 2(3x + 1) ..... but in (ii) , there's a - sign in between (8x - 3) & 2(3x + 1).
THE SIMILARITIES BETWEEN (i) & (ii) ARE (8x - 3) & 2(3x + 1).