# Math Help - algebra 2 please help fast >.<

1. ## algebra 2 please help fast >.<

Hey... Any one know what roster notation is? The notes i was given had a example of {-5,-4,-3,-2,-1,0...6} but... is that just listing all the numbers on a number line? or is it listing the bold dots on the number line?
also on set-builder notation how do i change a set builder notation into a interval notation? like how do i know witch side would have a ( or a [ for the equation? The problem for this is... {x|x > 10} The > has a line under it. my answer i put was (infinity (positive) , 10] ... Did i do this right? Thankz for the help XD ...
Order the given numbers from least to greatest. Then classify each number by the subsets of the real numbers to which it belongs. 2/3 , 6.17, sqrt28, -3 1/8, -4.9
i just don't really under stand the second part of the question "Then classify each number by the subsets of the real numbers to which it belongs."
Help please ^^

2. Originally Posted by shawns15
Hey... Any one know what roster notation is?

Symbollically, we use two common methods to write sets. The roster notation is a complete or implied listing of all the elements of the set. So and are examples of roster notation defining sets with 4 and 20 elements respectively. The ellipsis,  '', is used to mean you fill in the missing elements in the obvious manner or pattern, as there are too many to actually list out on paper.

The set-builder notation is used when the roster method is cumbersome or impossible. The set B above could be described by . The vertical bar, |'', is read as such that'' so this notation is read aloud as the set of x such that x is between 2 and 40 (inclusive) and x is even.'' (Sometimes a colon is used instead of |.) In set-builder notation, whatever comes after the bar describes the rule for determining whether or not an object is in the set. For the set the roster notation would be impossible since there are too many reals to actually list out, explicitly or implicitly.

The notes i was given had a example of {-5,-4,-3,-2,-1,0...6} but... is that just listing all the numbers on a number line? or is it listing the bold dots on the number line?
also on set-builder notation how do i change a set builder notation into a interval notation? like how do i know witch side would have a ( or a [ for the equation? The problem for this is... {x|x > 10} The > has a line under it. my answer i put was (infinity (positive) , 10] ... Did i do this right?

Not exactly. Interval notation for that would be $(10, +\infty)$

Thankz for the help XD ...

Order the given numbers from least to greatest. Then classify each number by the subsets of the real numbers to which it belongs. 2/3 , 6.17, sqrt28, -3 1/8, -4.9

Can you order these numbers from least to greatest. Not so hard!

i just don't really under stand the second part of the question "Then classify each number by the subsets of the real numbers to which it belongs."

Which of the following sets of numbers does each of those numbers belong? Here are your choices:

Real Numbers
Imaginary Numbers
Rational Numbers
Irrational Numbers
Integers (Pos/Neg Whole numbers and 0)
Natural Numbers

You may even have sets called Positive Whole Numbers and Negative Whole Numbers.

For example, 2/3 would belong to sets Real and Rational.

Help please ^^
I hope I answered your questions.

3. Originally Posted by masters
I hope I answered your questions.
Yeah it does thanks. So you know the part that i gave order the numbers and what not. Was just so u would have a example of what i was referring to with the instructions ^^ i knew how to put them in least to greatest. Thankz again