Factorise 28xy - 12x and y - 6x + 2xy - 3.

The GCF of the coefficients 28 and 12 is 4.
The GCF of the variables $xy$ and $x$ is $x$.
So, the GCF of $28xy$ and $12x$ is $4x$.

The answer is $\boxed{4x(7y - 3)}$.

Rearrange the terms to group those with common factors:

Group the first two terms and the last two terms:

For the first group $(y - 3)$, the common factor is 1.

For the second group $(-6x + 2xy)$, the common factor is $2x$.

So the expression becomes:

The answer is $\boxed{(y - 3)(1 + 2x)}$.