Scribe Post

Scribe Post for October 22 2010

In class today we talked more about how to solve compound inequalities with AND or OR. This is review from chapter 3 section 2.

Solving With And

1st treat both sides of the inequality like its own problem, so solve for both sides.
X+1<> 3
X <> 5
2nd Because the inequalities are joined by AND the solution will include all numbers between 8 and 5.

On a graph the problem would look like this: ___(___________)___
5 8

This shows that your answer is all numbers between 5 and 8.

Solving With OR

1st solve both sides of the problem individually.
6X – 4 < 2X or -3x < -9
-4 < -4X or X < 1
1>X or X > 3

2nd since the solution set are joined with OR the solution will include all the numbers either one of the two inequalities in step 1

Here’s how the problem looks in graph form: X>3 or X<1 color="#cc0000">+++++)+(+++++++++>
1 3
Because X can be all numbers less than one it can also be written as: (-∞, 1)
Because X can be all numbers greater than three it can also be written as: (3, ∞ )


Note: ( ) = < >
[ ] = ≤ ≥

4X ≤ 12
X ≤ 4
This can also be written as: (-∞, 4]

Ok, good stuff Next scribe will be Cole.