Question

Which property was used to simplify the expression?

3c-9+4c = 3c + 4c + 9
distributive property
communicative property
associative property
inverse property​

Answer 1

The change that happened from the first half of the equation to the second half was you moved the 9 and the 4c around.

Commutative property of addition allows you to do that. It's what says that 2+3 is the same thing as 3+2

Hope this helps you