Bus riders: 2c
Car riders: c
Walkers: 1/5c
Bus + Car + Walkers = Total
2c + c + 1/5c = 32
3
c = 32
c = 32
c = 32 (
c = 10
Bus: 2c = 2(10) = 20
Walkers:
c =
(10) = 2
Answer: Bus riders=20, Car riders=10, Walkers=2
-2-(+7) is the same thing at -2-7 which is -9

is the same thing as

which is

or

Last but not least the last one is the Associative Property based on definition listed below :)
Associative Property:<span> 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)</span>