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.
Use the zeroes to figure this out... x=-18, y=9
Answer:
the function is an exponential funtion.
Step-by-step explanation:
learned it
Answer: x= -4
Step-by-step explanation:
6x+9= -15
-9. -9
6x= -24
X= -4
Answer:
The cost must be $32 since that is the only cost possible for the 1st deal
Step-by-step explanation:
Let C represent the total cost of each deal
Let T be the number of trips down the water slide
C = 32 for the 1st deal since the cost is the same regardless of how much she rides
C = 18 + T for the 2nd deal
To find when the two costs are equal set them equal to each other and solve for T
32 = 18 + T
T = 14 trips
The cost must be $32 since that is the only cost possible for the 1st deal
