Answer:
12.6
Step-by-step explanation:
1/5 = .2
3/10 = .3
4.2 x .3 = 12.6
-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>
Answer:
7.93%
Step-by-step explanation:
504/100 = 5.04
40/5.04 = 7.93%