Pre Algebra (Period 2 & 4)

Inequalities & Their Graphs 2-8

What most real life situations call for

How often to you think...I need at least $20 (not exactly $20)
....
I want at most 20 minutes of homework (not exactly 20 minutes)?


Inequalities have many answers (most of the time an infinite number!)

Examples: n > 3 means that every real number greater than 3 is a solution! (but NOT 3)

n ≥ 3 means still means that every real number greater than 3 is a solution, 
but now 3 is also a solution


n < 3 means that every real number less than 3 is a solution! (but NOT 3)
 n ≤ 3 means still means that every real number less than 3 is a solution,   but now 3 is also a solution

 GRAPHING INEQUALITIES:
 First, graphing an equation's solution is easy
 1) Say you found out that y = 5, you would just put a dot on 5 on the number line
 2) But now you have the y ≥ 5
 You still put the dot but now also darken in an arrow going to the right showing all those numbers are also solutions
 I say: the equal sign part of it is a crayon...Pick up the crayon and color in the circle
 3) Finally, you find in another example that y > 5

You still have the arrow pointing right, but now you OPEN THE DOT on the 5 to show that 5 IS NOT A SOLUTION!

I say: there isn't a crayon so you can't color in the circle.
Therefore it stays open!
 

TRANSLATING WORDS:

Some key words to know:


AT LEAST means greater than or equal that is...
≥

AT MOST means less than or equal. THat is ≤


I need at least $20 to go to the mall means I must have $20, but I'd like to have even more!


I want at most 15 minutes of homework means that I can have 15 minutes, but I'm hoping for even less!