How do you solve for x in #| 4 - 2x| ≤ 8#?

1 Answer
Mar 4, 2018

See a solution process below:

Explanation:

The absolute value function takes any term and transforms it to its non-negative form. Therefore, we must solve the term within the absolute value function for both its negative and positive equivalent.

#-8 <= 4 - 2x <= 8#

First, subtract #color(red)(4)# from each segment of the system of inequalities to isolate the #x# term while keeping the system balanced:

#-8 - color(red)(4) <= 4 - color(red)(4) - 2x <= 8 - color(red)(4)#

#-12 <= 0 - 2x <= 4#

#-12 <= -2x <= 4#

Now, divide each segment by #color(blue)(-2)# to solve for #x# while keeping the system balanced. However, because we are dividing inequalities by a negative number we must reverse the inequality operators:

#(-12)/color(blue)(-2) color(red)(>=) (-2x)/color(blue)(-2) color(red)(>=) 4/color(blue)(-2)#

#6 color(red)(>=) (color(blue)(cancel(color(black)(-2)))x)/cancel(color(blue)(-2)) color(red)(>=) -2#

#6 >= x >= -2#

Or

#x >= -2#; #x <= 6#

Or, in interval notation

#[-2, 6]#