The term "closed" in math means that if you take two items from a set, do some operation, then you'll always get another value in the same set (sometimes you may get the same value as used before). For example, adding two whole numbers leads to another whole number. We therefore say "the set of whole numbers is closed under addition". This applies to integers as well because integers are positive and negative whole numbers. So we can say that integers are closed under addition.
Integers are not closed under division. Take two integers like 2 an 5 and divide: 2/5 = 0.4 which is not an integer. Integers don't have decimal parts.
The set of whole numbers is {0,1,2,3,...} and we can subtract the two values 1 and 2 to get 1-2 = -1. The order matters here. Subtracting a larger value from a smaller leads to a negative. The value -1 is not in the set of whole numbers. So we can say that whole numbers is not closed under subtraction
Finally, the set of irrational numbers is closed under addition. Adding any two irrational numbers leads to another irrational number. For instance, pi+sqrt(2) = 3.142 + 1.414 = 4.556; I'm using rounded decimals as approximate values. An irrational number is one where we cannot write it as a fraction of integers. Contrast that with a rational number in which we can write it as a fraction of integers. Example: 10 = 10/1 is a rational number.
Answer:
- D.
Step-by-step explanation:
<u>Given function:</u>
<u>Equivalent expression is:</u>
Correct choice is D
Answer:
B
Step-by-step explanation:
Their selling price was 2.45 times the price they bought it. If they split the profit evenly and there was two of them, multiply their profit by two and divide that number by 800 to find how much more they sold it for, so they sold it for 245% more than they bought it
Answer:
The function 
is represented by 
.
Step-by-step explanation:
Statement indicates that atmospheric pressure decreases exponentially when height above sea level is increased. This fact is represented by the following model:
(Eq. 1)
Where:
- Atmospheric pressure at sea level, measured in kilopascals.
-Atmospheric pressure decrease rate, dimensionless.
- Height above sea level, measured in kilometers.
- Current pressure, measured in kilopascals.
If we know that 
and 
, the function is represented by:
