1) The rational compound inequality is - 2 < - 8/x < 4.
\Write the rational compound inequality using the word and. Then solve each inequality.
\- 2 < - 8/x and - 8/x < 4.
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- Step-1 \
State the exclude values,These are the values for which denominator is zero.
\The exclude value of the inequality is 0.
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- Step - 2 \
Solve the related equation.
\- 2 = - 8/x and - 8/x = 4.
\- 2x = - 8 and - 8 = 4x.
\x = 4 and x = - 2.
\Solutions of related equation x = 4 and x = - 2.
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- Step-3 \
Draw the vertical lines at the exclude value(x = 0) and at the solution (x = 4 and x = - 2) to separate the number line into intervals.
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- Step-4 \
Now test a sample value in each interval to determine whether values in the interval satisify the original inequality - 2 < - 8/x < 4.
\Test Iinterval x - value Inequality Conclusion
\ x = - 3 - 2 < - 8/(- 3) < 4 ⇒ - 2 < 2.67 < 4 True.
(- 2, 0) x = - 1 - 2 < - 8/(- 1) < 4 ⇒ - 2 < 8 < 4 False.
\(0, 4) x = 1 - 2 < - 8/(1) < 4 ⇒ - 2 < - 8 < 4 False.
\(4, ∞) x = 5 - 2 < - 8/(5) < 4 ⇒ - 2 < 1.6 < 4 True.
\The above conclude that the inequality is satisfied for all x - values in (- ∞, - 2) and (4, ∞). This implies that the solution of the inequality - 2 < - 8/x < 4 is the interval (- ∞, - 2) U (4, ∞), as shown in Figure 1.31. Note that the original inequality contains a “less than” symbol. This means that the solution set does not contain the endpoints of the test intervals are (- ∞, - 2) and (4, ∞).
\The statement is true for x = -0.1 and x = 0.05.Therefore the solution is x < -1/15 and x >0.
\Solution x < -1/15
\x > 0.
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