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Sometimes we have equations that don't use an equal sign (=). |
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| They use one of 4 other squiggles. | ||
| The contestants are: | ||
| # 1 | ||
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| This means "greater than". | ||
| It means the stuff on the left side of the equation | ||
| has a greater value than the stuff on the right side. | ||
| Another way to think of inequalities, is that in all of these problems | ||
| the inequality arrow always points towards the stuff with less value. | ||
| As in: | ||
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| # 2 | ||
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| This puppy means "less than". | ||
| It means that the stuff on the left side of the equation | ||
| has a lesser value than the stuff on the right side. | ||
| As in: | ||
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| # 3 | ||
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| This one means "greater than OR equal to". | ||
| It is a combination of ">" and "=". | ||
| It means that the stuff on the left side | ||
| either has a greater value or is of equal value | ||
| than the stuff on the right side. | ||
| As in: | ||
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| # 4 | ||
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| The last of our musketeers. | ||
| This one means "less than OR equal to". | ||
| It is a combination of "<" and "=". | ||
| It means that the stuff on the left side | ||
| either has a lesser value or is of equal value | ||
| than the stuff on the right side. | ||
| As in: | ||
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| When you get an equation with one of these things in it, | ||
| it makes NO DIFFERENCE in how you work the problem. | ||
| Just use the same two rules in the same way. | ||
| There is ONE EXTRA DETAIL | ||
| that you need in some of these problems. | ||
| If you multiply or divide both sides by a negative number, | ||
| you reverse the direction that the inequality arrow points. | ||
| OK, now we're ready to try some problems! | ||
| Example: | ||
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5X - 3 > 2 |
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| First you add 3 to both sides ... | ||
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| Now divide both sides by 5 | ||
| to get the X all by itself. | ||
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| And simplify ... | ||
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X > 1 |
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| OK, now in this next example, | ||
| we will need that "reverse the direction" trick. | ||
| Solve this for X ... | ||
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| First peel the "+ 1" away from the X. | ||
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| Now divide by -3 and watch the inequalities | ||
| change direction ... | ||
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copyright 2005 Bruce Kirkpatrick |
