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:
Answer:
x = -2
Step-by-step explanation:
Arrange 6x + y= -5, -6x + 12y=96 vertically:
6x + y= -5
-6x + 12y=96 Now combine like terms:
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13y = 91
Solving for y by dividing both sides by 13: y = 7
Find x by substituting 7 for y in the second equation: -6x + 12(7) = 96
Then -6x = -84 + 96, or:
-6x = 12, and so x = -2
Answer:
126
Step-by-step explanation:
A line is 180 degrees. I found the degree of the angles in-between 126 and M by subtracting 126 from 180. This means that M is also 126. (Plus the intersecting lines are parallel)
