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Solving Inequalities
Properties of Inequalities For all real numbers a,
b, c:
Rule 1 |
If a < b, then b > a |
Rule 2 |
If a < b, then -a > -b |
Rule 3 |
If a < b, then for all real numbers c, a + c < b
+ c |
Rule 4 |
If a < b, then for all POSITIVE c, ac < bc |
Rule 5 |
If a < b, then for all NEGATIVE c, ac > bc |
Solution sets to a linear inequality can be shown using
table 2.6(pg 174)
Steps to Solving a Linear Inequality
(The < sign here could be ANY inequality.) |
1. Eliminate fractions by multiplying both sides
by the least common denominator. KEEP THE LCM POSITIVE! |
2. Remove grouping symbols using the distributive
property |
3. Simplify each side by combining like terms.
(ax + b < cx + d) |
4. Use addition property of equality to isolate
the variable. (gx + b) < d |
5. Use addition property of equality to isolate
the constant term. to get the
equation into the form (gx < h). |
6. If g > 0, use the multiplication property of
equality to solve for x (x < k). |
7. If g < 0 use the multiplication property of
equality to solve for x and CHANGE the direction of the inequality. |
8. Check your solution in the original inequality
by substitution. |
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