Natural numbers are closed under division: false.
A set is closed under a certain operation if the results of that operation are always inside that set.
So, if natural numbers were closed under division, the division of two natural numbers would always be a natural number.
You have plenty of counterexamples, to pick one you may divide any odd number by 2: 5/2 is not a natural number.
Negative numbers are closed under addition: true.
Let 
be two positive numbers. So, 
are two negative numbers. Their sum is
And since 
is positive, we deduce that 
is negative, so the sum of two negative numbers is still negative.
Prime numbers are closed under subtraction: false.
This would mean that the subtraction of two primes is also a prime. Again, there are many counterexamples: 7 is prime and so is 3, but their difference 7-3 is 4, which is not prime.
Answer:
X = 9 and Y = 8
Step-by-step explanation:
We are to find the midpoint of the coordinates (13,15) and (5,1).
Using the midpoint formula;
M(X, Y) = [(x1+x2)/2, (y1+y2)/2]
X = (x1+x2)/2
Y = (y1+y2)/2
From the coordinates, x1 = 13, y1 = 15, x2 = 5 and y2 = 1
X = 13+5/2
X = 18/2
X = 9
Similarly;
Y = 15+1/2
Y = 16/2
Y = 8
Hence The Tourist Information Center is located at point X = 9 and Y = 8
Multiply the x part by -3 to cancel out the fraction, so the final answer will be x + 24. You could also multiply by 3 then divide by -1 to change the signs
Answer: Hi!
The solution to positive 6 and -6 is 0. A negative and a positive of the same absolute value cancel out.
Hope this helps!
Answer:
54
Step-by-step explanation:
3/(1/2)=6
6x9=54 mi
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