One of the equations demonstrates both the commutative and the associative properties for addition:
(A) (4 + 3) + 2 = 4+ (3 + 2)
(B) 18 + 57 = 57 + 18
(C)(5 + 6) + 7 = 6+ (5 + 7)
(D)3 +4 + 5 = (3 + 4) + 5

50-38=12

step-by-step explanation:

lol we need to see what the question is asking about

step-by-step explanation:

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step-by-step explanation:

see explanation

step-by-step explanation:

a

(6r + 7) + (13 + 7r) ( remove brackets and collect like terms )

= 6r + 7 + 13 + 7r

= 13r + 20

b

remove brackets and collect like terms

13 - r - 1 + r

= 12 - r

c

remove brackets and collect like terms

= - 8 - r + 2r - 4

= - 12 + r

d

remove brackets and collect like terms

= 7r - - - 6r

[-   - = - - = - ]

= r -