Answer: B. 
Step-by-step explanation:
1. By definition, the associative property of addition is:

2. Therefore, if you have the following expression:

You apply the Asociative property of addition by regrouping the numbers as following:

3. Then, you can conclude that the correct option is B.
Let's say, the number is "a"
thus

cross-multiply and solve for "a"
Answer:
I think the first one is correct
Answer:
True
Step-by-step explanation:
angle 3 and 6 are alternate angles.
alternate angles have the following characteristics:
1. they are inside the parallel lines
2. they are on opposite sides of the transversal
3. they are EQUAL
another example of alternate angles is angle 4 and angle 5
Answer:
25
Step-by-step explanation:
because there are vertical angles