How do you factor #2d^2g+2fg+4d^2h+4fh#?
Sometimes the associations can be spotted more easily than at other times.
You are looking for repeats. Notice that there are two
So lets experiment!
Grouping by coefficients (numbers) so that they can be factored out.
looking for common factors & considering the first brackets gives:
This is the same as:
There is no need to experiment further as we have found the answer.