Pearson Algebra 1 Common Core, 2011
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Pearson Algebra 1 Common Core, 2011 View details
6. Compound Inequalities
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Exercise 14 Page 204

Split the compound inequality into two separate ones and solve them individually.

Solution: 14 ≤ k ≤ 26
Graph:

Practice makes perfect

We are given the following compound inequality. 15 ≤ 20+11+k/3≤ 19 Sometimes, it can be helpful to write a compound inequality as two individual inequalities. This lets us solve each one separately. 15 ≤ 20+11+k/3 and 20+11+k/3 ≤ 19Now we can solve them separately, and later combine their solution sets.

First Inequality

Inequalities can be solved in the same way as equations, by performing inverse operations on both sides until the variable is isolated. The only difference is that when you divide or multiply by a negative number, you must flip the inequality sign.

15 ≤ 20+11+k/3
45 ≤ 20+11+k
45 ≤ 31 +k
14 ≤ k
k ≥ 14

The first inequality is satisfied by all values greater than or equal to 14. Note that k can equal 14 as the inequality is non-strict.

Second Inequality

Once more, we will solve the inequality by isolating the variable.

20+11+k/3 ≤ 19
â–¼
Solve for k
20+11+k ≤ 57
31+k≤ 57
k≤ 26

The second inequality is true for numbers less than or equal to 26. Notice that k can equal 26 as the inequality is non-strict.

Combining Solution Sets

Finally, we can combine the obtained solution sets. The first inequality, k ≥ 14, describes all values greater than or equal to 14. To show this on a number line, we can mark a closed circle at 14 —because k can equal 14 — and shade the region to the right.

The second inequality, k ≤ 26, describes all values less than or equal to 26. To show this on a number line, we can mark a closed circle at 26 — because k can equal 26 — and shade the region to the left.

The intersection of these solution sets, 14 ≤ k ≤ 26, describes the solution set to the compound inequality.