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:
Distribution, equal groups, skip counting, repeated addition, and array.
Step-by-step explanation:
Sure thing!
So if we look at the function, it is an exponential, meaning that it is a number to the power of x
The graph can be described by the equation
y = a^x
If we look at the graph, one of the points on the line is (2, 16), the x value is 2 and the y value is 16
If we consider this along with the function for the graph, we can say that
16 = a^2
Just solve this for a and you’ll have your answer :)
Answer:
Chicken is $8
Duck is $5
Step-by-step explanation:
Step 1: Let 
represent the cost of chickens and let 
represent the cost ducks. Since we have two unknowns, we need two equations to find them.
Step 2: The total cost of chickens Michael sold last month can be shown as 
, and the total cost of ducks he sold last month can beshown as 
Since these together add up to 550, we get these equations:
We are also given that this month, Michael sold 44 chickens, and 36start text, 36 ducks, $532. This equaion can be expressed as:
Now that we have a system of the two equations, we can now go ahead and solve the two equations.
Step 3: We can now solve the system of equations by using the elimination method. Manipulate the equations so one of the variables has the same coefficients but with opposite signs.
Now eliminate
When we solve the resulting equation, we obtain that 
. Then, we can substitute this into one of the original equations and solve for to obtain 
.
Step 4: Recall that denotes the cost of a chicken and denotes the cost of a duck. Therefore, a chicken costs $8, and a duck costs $5
