Question

.

Answer 1

its like this :

a + (b + c) = (a + b) + c

?

Answer 2

its some weird symbol times 7 = 7 times weird symbol

Answer 3

i dont see any 7=7 in the link provided hmm

Answer 4

Oh sorry wrong one! lol

Answer 5

but yes it's like that

Answer 6

have a look at this page and tell me if it helps or not

http://www.aaastudy.com/pro74ax2.htm

Answer 7

Some of the basic rules are

Commutative property of addition : x+y = y+x
Associative property of addition : x+(y+z) = (x+y)+z
Additive Identity Property: x+0 = x, 0+x = x
Distributive property: x(y+z) = x*y + x*z

One of those rules listed above is your answer

Answer 8

associative property of addition?

Answer 9

you nailed it