Remember : An Equation behaves like a Balance.

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INTRODUCING INEQUALITIES
Remember An Equation behaves like a
Balance. The Left Hand Side of the equals is one
side of the scales. The Right Hand Side of the
equals is the other side.
A BALANCED EQUATION
Add 1 to both sides
STILL BALANCED
Now add -3 to both sides
STILL BALANCED
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What if the equals was replaced by a GREATER THAN
sign (gt)? Or a LESS THAN sign (lt) ?
THE GOLDEN RULES STILL APPLY
GOLDEN RULES
Solve for x means get x on its own on one side of
the equation
What you do to the LHS you do to the RHS
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x is not on its own. Whats blocking us?
Its 1
So Add -1 to both sides
x must be greater than 2 (As expected!)
Lets Check
Pick a number greater than 2. Say 5
Correct!
Are there any other numbers greater than 2 ?
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Try x4
Try x3
Try x2
Try x1
Which numbers greater than 2 to choose?
Anything even slightly greater than 2 will make
this inequality TRUE
YES
NO
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Which numbers greater than 2 to choose?
3 sets of Numbers that x can be an element of
Natural Numbers (N)
Finger Counting
Integers (Z)
Real Numbers (R)
Any number you can put into this!
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Same Solution WHY?
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Same Solution WHY?
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YOU TRY THEM
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2 Really Good Websites
http//www.onlinemathlearning.com/algebra-inequali
ties.html
Great for all Algebra. Includes Games and Video
examples.
http//www.mathplayground.com/howto_InequalitiesA.
html
A really clear video of how to solve inequalities
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GOLDEN RULE
Solve for x means Get x on its own on one side
of the inequality
So xlt2 is solved. But x3lt2 is not yet solved.
Is 3xgt12 solved yet?