About Absolute Value & the Distance Between Two Points on a Number Line:

When we think about absolute value, we are thinking about the distance between a number and zero on the number line. Since a distance is always non-negative, meaning it is either zero or some positive value, the absolute value of a number is always non-negative. The absolute value of a number is just the number if it is a non-negative number or the opposite of the number if it's a negative number.


Test Objectives
  • Demonstrate an understanding of how to Simplify an Absolute Value Expression
  • Demonstrate an understanding of how to Solve a Simple Absolute Value Inequality
  • Demonstrate an understanding of how to find the Distance Between Two Points on a Number Line
Absolute Value & the Distance Between Two Points on the Number Line Practice Test:

#1:

Instructions: Simplify each.

$$a)\hspace{.2em}-|-3|$$

$$b)\hspace{.2em}|-5 \cdot 7 + 2^2|$$


#2:

Instructions: Solve each inequality for x.

$$a)\hspace{.2em}|x| > -12$$

$$b)\hspace{.2em}|x| < -8$$


#3:

Instructions: Solve each inequality for x.

$$a)\hspace{.2em}|x| < 7$$

$$b)\hspace{.2em}|x| > 9$$


#4:

Instructions: Find the distance between Point "Q" and Point "R" on the number line.

$$a)\hspace{.2em}Q=-5, R=7$$

$$b)\hspace{.2em}Q=-1, R=8$$


#5:

Instructions: Find the distance between Point "Q" and Point "R" on the number line..

$$a)\hspace{.2em}Q=-3, R=-1$$

$$b)\hspace{.2em}Q=12, R=-15$$


Written Solutions:

#1:

Solutions:

$$a)\hspace{.2em}-3$$

$$b)\hspace{.2em}31$$


#2:

Solutions:

$$a)\hspace{.2em}All \hspace{.25em}Real \hspace{.25em}Numbers$$ $$(-\infty, \infty)$$

$$b)\hspace{.2em}No \hspace{.25em}Solution$$ $$∅$$


#3:

Solutions:

$$a)\hspace{.2em}-7 < x < 7$$ $$(-7, 7)$$

$$b)\hspace{.2em}x < -9 \hspace{.25em}or \hspace{.25em}x > 9$$ $$(-\infty, -9) ∪ (9, \infty)$$


#4:

Solutions:

$$a)\hspace{.2em}12$$

$$b)\hspace{.2em}9$$


#5:

Solutions:

$$a)\hspace{.2em}2$$

$$b)\hspace{.2em}27$$