It affects the answer because parentheses signifies or implies that yoy are doing the operation inside of their that step comes first because if you forget about that step and move on it will affect your answer and you will get it wrong write this down
Notice the table of values, thus let's pick two points from it, to check what the slope may be,

Diagonal angles have the same measure - not sure what u mean by oposite.
answer: you're missing the problem