1 True.(For every integer square we can find a larger integer)
2.True.
3.True.(Since the domain is integer , for n=-m the condition holds)
4.True.(For n=1 , multiplying it with any integer gives the integer itself.)
5.True(4+1=5)
6.False (No such pair exists)
7.False , since n+m=4 . 4 is even , thus n and m both should be even or both should be odd , even - even = even and odd-odd=even . Thus n-m=1 is not possible.
8.True , 3+1=4 and 3-1=2
9.False .