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Section 4.3: Solving Compound Inequalities Worksheet 4.3

Vocab: A compound inequality is an inequality made up of two or more inequalities in the same variable.

Examples:

$4x-2>0$ OR $2x+5<-2$

$5x+2>-4$ AND $3x-3<3$

$-x-3<3x-5 \leq- x$







Solutions to Linear Inequalities.

Example: Verify that $x=1$ is a solution to the compound inequality $5x+2>-4$ AND $3x-3<3$.

Example: Verify that $x=2$ is NOT a solution to the compound inequality $5x+2>-4$ AND $3x-3<3$.

Example: Verify that $x=1$ is a solution to the compound inequality $4x-2>0$ OR $2x+5<-2$.

Example: Verify that $x=1$ is a solution to the compound inequality $-x-3<3x-5 \leq -x$.







Finding Solution Sets to Compound Inequalities

Example: Solve the compound inequality $4x-2>0$ OR $2x+5<-2$.

Also, graph the solution set and write it in interval notation.















Solution Sets to Compound Inequalities

Example: Solve the compound inequality $5x+2>-4$ AND $3x-3<3$.

Also, graph the solution set and write it in interval notation.















Solution Sets to Compound Inequalities

Example: Solve the compound inequality $-x-3 < 3x-5 \leq -x$.

Also, graph the solution set and write it in interval notation.















Gremlin Case I: No solution.

Example: Solve the compound inequality $3x-3>0$ AND $4x+1 \leq 5$.













Gremlin Case II: Solution set equals $\mathbb{R}$, or $(-\infty,\infty)$

Example: Solve the compound inequality $3x+5\geq-4$ OR $5x+2\leq -1$.















In Summary

Solutions to OR inequalities:





Solutions to AND inequalities: