The answer is A because when you plug in the points into the distance formula, you will get square root of 17 squared plus 17 squared. Hope this helps!
This appears to be just an expression we are simplifying, not an equation we are solving. I THINK you are saying that the expression looks like this:

If you rationalize the denominator, you would get this expression:

which, after simplifying, looks like this:

and that's as simple as I can see that one getting. You can't factor anything out of the denominator to cancel with the numerator, so I think you're as simple as you can get there!
Answer: you sold 10 adult tickets and 11 children tickets.
Step-by-step explanation:
Let x represent the number of adult tickets that you sold.
Let y represent the number of children tickets that you sold.
You sold a total of 21 tickets. This means that
x + y = 21
Admission prices are six dollars for adults and four dollars for children. You sell tickets for admission to your school play and collect a total of $104. This means that
6x + 4y = 104 - - - - - - - - - -1
Substituting x = 21 - y into equation 1, it becomes
6(21 - y) + 4y = 104
126 - 6y + 4y = 104
- 6y + 4y = 104 - 126
- 2y = - 22
y = - 22/ -2 = 11
Substituting y = 11 into x = 21 - y, it becomes
x = 21 - 11 = 10