We can solve this problem by using the distance formula. The distance formula is: 
We can now put in values and solve.
The correct answer would be 20
"A" is the answer because there are six sides, and each side is x+y, so it could be stated 6(x+y), but if you distribute the six in, you get 6x + 6y.
To factor out -1/3 out of the expression -1/3x - 8, first divide -8 by -1/3 to get 24. Now just put 24 in the place of -8 in the original expression. Your final answer should be -1/3(x + 24). Hope this helps and have a phenomenal day!
To solve this just put a 1 over the 15. So it would be 12/7 + 15/1 which is 16 5/7.
