10-11 Compound inequalities - class notes

A compound inequalitiy is two inequality statements joined by the words "and" or "or".

Refer to the notes on page 47, item 20

x > -1 and x < 4

x < 3 or x > 6

The numbers that satisfy the compound inequality and the graph of the compound inequality are
the junction of two sets.

Conjunction goes with the word "and".  It means the numbers must satisfy both inequalities.  The graph is where the tails of the two graph arrows overlap.  The graph looks like a segment. The graph could have open or closed dots at its ends.    

x > -1 and x < 4

Disjunction goes with the word "or".  It means the numbers only have to satisfy one of the inequalities.  The graph is two arrows pointing in opposite directions.  The graph has a gap between the arrows.  The arrows are split.

x < 3 or x > 6

Homework for 10-12:  page 48, items a, b, c, d, e.

Hint:  Some exercises are counted only with whole numbers.  Use the idea of "between" to form the graphs.