I don't get how to do this?
Can someone help please!

In the following example of "Simplifying an Expression", what reason would be used for step C?

Simplify the expression 3k + 7 + 2k and justify each step

3k + 7 + 2k = 3k + 2k + 7 A
= (3k + 2k) + 7 B
= (3 + 2)k + 7 C
= 5k + 7 D
A. Addition
B. Commutative Property
C. Associative Property
D. Distributive Property

Question

I don't get how to do this?
Can someone help please!

In the following example of "Simplifying an Expression", what reason would be used for step C?

Simplify the expression 3k + 7 + 2k and justify each step

3k + 7 + 2k = 3k + 2k + 7         A
                    = (3k + 2k) + 7      B
                    = (3 + 2)k + 7        C
                    = 5k + 7                 D
	A.	Addition
	B.	Commutative Property
	C.	Associative Property
	D.	Distributive Property

anonymous · Answer

You are using the Distributive Property "backwards".  Usually, the Distributive Property is stated as:  A(B + C) = AB + AC, but in this case you are going the other direction.  AB + AC = A(B + C), or in this particular case 3k + 2k = (3 + 2)k.