Answer:
France and England Declared war on Germany and we all know where this went
Explanation:
When Germany and the USSR Invaded Poland, this resulted in a declaration of war between the allies (excluding Neutral United States) and Germany. This lead to the Start of World War 2
also the reason why that Britain did not help Poland was that Britain thought that the USSR was going to help Poland (I don't Know about this i watched a country balls or a History Matters Video about this topic)