Sarai, let's break it apart. Just like 2/3 = 1/3 + 1/3.
16x3/8x3 = 16xxx/8xxx. 16/8 = 2, and each x/x = 1 so they cancel out.
8x2/8x3 = 8xx/8xxx. 8/8 = 1, each x/x = 1, and we are left with 1/x.
16x/8x3 = 16x/8xxx. Again, 16/8 = 2. x/x = 1 and we are left with 2/xx = 2/x2.
Put them all together for your answer.