Answer:
Step-by-step explanation:
from line 1 to line 2 we see that (2 + 9x ) is the same as (9x +2 ) because
commutative propriety of addition
(we commute numbers around an addition sign)
from line 1 to line 2 we see that (x+1)*(9x +2) is the same as (9x+2)*(x+1) because commutative propriety of multiplication
(we commute parentheses around a multiplication sign)
