Question

Please help me answer these!!! Thanks :)

Answer 1

-2-(+7) is the same thing at -2-7 which is -9


`-3 (2)/(7) -(- (5)/(7) )` is the same thing as
`(-3 (2)/(7)) + ((5)/(7))` which is
`- (18)/(7)` or
`-2 (4)/(7)`

Last but not least the last one is the Associative Property based on definition listed below :)
Associative Property: When three or more numbers are added, the sum is the same regardless of the grouping of the addends. For example (2 + 3) + 4 = 2 + (3 + 4)