Answer: [beautiful math coming... please be patient] $2x(3 - 4y)$

Here's what's going on:

[beautiful math coming... please be patient] $6x - 8xy$	Ignore the plus/minus signs of the terms for the moment, and find the greatest common factor of $\,6x\,$ and $\,8xy\,$, which is $\,2x\,$.
[beautiful math coming... please be patient] $= \overset{\text{gcf}}{\overbrace{(2x)}}(3) - \overset{\text{gcf}}{\overbrace{(2x)}}(4y)$	Rename each term as the greatest common factor, times the remaining factors. Eventually, you won't need to write down this intermediate step.
[beautiful math coming... please be patient] $= (2x)(3 - 4y)$	Use the distributive law, backwards!

Answer: [beautiful math coming... please be patient] $x^2y(3 + 5y)$

Note:   In the web exercise below, you would input this answer as:   x^2y(3 + 5y)
Notice that exponents are input using the ‘ ^ ’ key.
Variables must appear in the same order as in the original expression, going from left to right.
For example, although   yx^2(3 + 5y)   or   x^2y(5y + 3)   are correct answers, they are not recognized as correct.