Post on 04-Jan-2016
Compound Inequalities
andEleanOR theice skater
with the word “OR”
Graphs pointing the same way
Graph the inequalities on two separate number lines
drawn one above the other
X>5 5(---------------------------
X>7 7(----------------
EleanOR can skate on either foot as long as she has ice under her.
In this case, she can start skating on her left foot at 5 and skate all the way to + infinity
ANSWER (5, + oo)
Graphs pointing opposite ways - overlap
Graph the inequalities on two separate number lines
drawn one above the other
X>5 5(---------------------------
-------------------------------------)9 x<9
EleanOR can skate on either foot as long as she has ice under her.
In this case, she can start skating on her right foot at - infinity
and skate on her left foot all the way to + infinity.
ANSWER: ( - oo, + oo)
Graphs pointing opposite ways – NO overlap
Graph the inequalities on two separate number lines
drawn one above the other
X>5 5(---------------------------
----------)2 x<2
EleanOR can skate on either foot as long as she has ice under her.
In this case, she can start skating on her right foot at - infinity, and skate all the way to 2. Then she needs to hop on a golf cart to get to 5, at which point she can skate on her left foot all the way to + infinity.
ANSWER: ( - oo, 2) U (5, + oo)
Graphs pointing opposite ways – almost overlap
Graph the inequalities on two separate number lines
drawn one above the other
X>5 5(---------------------------
----------)5 x<5
EleanOR can skate on either foot as long as she has ice under her.
She can start skating on her right foot at – infinity and skate all the way to 5. Then she needs to hop over 5
and skate on her left foot all the way to + infinity
ANSWER: ( - oo, 5) U (5, + oo)
EleanORthe skater!
Remember her when your
inequalities are joined by the word
“OR”
And you’ll be the champion!