The GCF is 4, so you can take that out and put it in front of the parentheses. Then you just divide all of the terms by 4 (4xy / 4 = xy; 12w / 4 = 3w; 12z / 4 = 3z), etc.
The two large triangles can be proven congruent through SSS ASA and SAS, you have all the congruent angles and sides you could ever need to prove the two large triangles congruent in at least 3 ways
