The equality 8.3a + (4b +-3.2)=8.3a + 4b +3.2c can be justified by associativity.

Answer 1

Be careful!!!!

You have 3.2C there on the right side.!!!!!! Typo????

Otherwise YES, BECAUSE IT IS ALL ADDITION, you can drop the parenthesis,

as the associative and commutative property allows addition in any order