About Solving Absolute Value Inequalities:

Recall that the absolute value of a number is the distance from that number to zero on the number line. When we see an absolute value inequality such as |x| > 5, we find our solution as all the numbers whose absolute value is greater than 5. In other words, we're looking for numbers that are more than 5 units away from zero in either direction. The answer would be x < -5 or x > 5. Similarly, if we look at |x| < 5, we find our solution as all the numbers whose absolute value is less than 5. In other words, we're looking for numbers that are less than 5 units away from zero on the number line. The answer would be -5 < x < 5.


Test Objectives
  • Demonstrate a general understanding of absolute value
  • Demonstrate the ability to solve a compound inequality with "and" or "or"
  • Demonstrate the ability to solve an absolute value inequality
Solving Absolute Value Inequalities Practice Test:

#1:

Instructions: Solve each inequality, write the solution in interval notation, and graph the interval.

a) 5 - 3|9p + 9| ≤ -103


#2:

Instructions: Solve each inequality, write the solution in interval notation, and graph the interval.

a) $$\frac{3}{2}\left|1 + \frac{1}{3}x\right| + \frac{5}{2}≥ \frac{8}{3}$$


#3:

Instructions: Solve each inequality, write the solution in interval notation, and graph the interval.

a) 9 + 4|8n - 2| ≤ 49


#4:

Instructions: Solve each inequality, write the solution in interval notation, and graph the interval.

a) 2|5 - 2a| + 6 < 4


#5:

Instructions: Solve each inequality, write the solution in interval notation, and graph the interval.

a) $$-\frac{3}{2}\left| -1 + \frac{2}{3}v \right| + 2 ≥ 1$$


Written Solutions:

#1:

Solutions:

a) p ≤ -5 or p ≥ 3

(-∞,-5] ∪ [3,∞)

graphing an interval on the number line


#2:

Solutions:

a) $$x ≤ -\frac{10}{3}$$ or $$x ≥ -\frac{8}{3}$$

$$\left(-∞,-\frac{10}{3}\right] ∪ \left[-\frac{8}{3}, ∞\right)$$

graphing an interval on the number line


#3:

Solutions:

a) $$-1 ≤ n ≤ \frac{3}{2}$$

$$\left[-1,\frac{3}{2}\right]$$

graphing an interval on the number line


#4:

Solutions:

a) No solution: ∅


#5:

Solutions:

a) $$\frac{1}{2}≤ v ≤ \frac{5}{2}$$

$$\left[\frac{1}{2},\frac{5}{2}\right]$$

graphing an interval on the number line