12a³-12a²＋3ab² -4mx²＋8mx-4m

12a³-12a²＋3ab² -4mx²＋8mx-4m
12a³-12a²＋3ab²
-4mx²＋8mx-4m

12a³-12a²＋3ab² -4mx²＋8mx-4m
12a³-12a²b＋3ab²
=3a(4a²-4ab+b²)
=3a(2a-b)²
-4mx²＋8mx-4m
=-4m(x²-2x+1)
=-4m(x-1)²