Algebra 1
posted by
Hannah on
.
What property justifies that 3y+9 = 9+3y

Algebra 1 
helper,
3y + 9 = 9 + 3y
Commutative Property
For addition, the rule is
a + b = b + a
in numbers, this means 2 + 3 = 3 + 2

Algebra 1 
Mia,
What property justifies:
6a+(2a+8b)