Using the Associative Property of addition, if you move the parentheses anywhere between a, b, and c, the answer will always be the same. Also, the Commutative Property of addition states that if you move the terms around, the answer is also still the same. So, (a+b)+c is the same as b+(a+c).
I'm pretty sure A, and C but I'm not very sure about B I hope that helped.
The correct choice is D.) No solution
The top question is B. 30, because you have to set 7y-30 equal to 4y+60 since both lengths are the same.
