This is done by factoring. 1/8 is smaller than 1/2, so we can factor a 1/8 out of 1/2. This is what that looks like:
![( (1)/(2) )/( (1)/(8) )](https://img.qammunity.org/2019/formulas/mathematics/college/6dy95i9s27e9317qwa2xzyda3l8jnp3pzv.png)
, because factoring after all is a form of division. When we divide a fraction by a fraction, we bring the lower fraction up and flip it to multiply, giving us this:
![(1)/(2) * (8)/(1)](https://img.qammunity.org/2019/formulas/mathematics/college/1d5ok2ywvp5hdmnvhhb9rh37tu694j6c5b.png)
. This of course reduces to 4. So when we factor out 1/8, what we will have then is
![(1)/(8) (x-4)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/2tyq8hbgidxuaci2vsu2p59ukp22gab0ns.png)
, choice D from above.