Answer:
1.16 is the answer
Step-by-step explanation:
The question is a bit ambiguous: you may mean

or

Anyway, in both cases, the domain of a function involving a square root is found by imposing the content of the root to be greateer than or equal to zero. So, in the first case you have

In the second case, you have

It has no solution. The statement is false for any value x and y therefore the system of equations has no solution.
<h3>
Answer: 29,030,400</h3>
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Explanation:
Let's say the mother will temporarily take the place of all the sisters. Wherever the mother sits will represent the block of girls.
Taking out the 6 sisters and replacing them with the mother leads to 7+1 = 8 people in a line.
There are 8! = 8*7*6*5*4*3*2*1 = 40,320 different ways to arrange 8 people.
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Again, the mother's position is where the sisters block will go. So let's say the mother was in seat #2. This would mean one brother would take seat #1, and all of the sisters would take the next six seats, until we reach seat #7 is when another brother would take the next seat.
Within any given permutation (the 40320 mentioned), there are 6! = 6*5*4*3*2*1 = 720 different ways to arrange just the girls in that girls block/group.
All together, there are 40320*720 = 29,030,400 different ways to arrange the 13 siblings where all the girls are seated together.