Let's solve this and find out what the solutions are
3 l 4 - 5x l = 9
3|4-5x| = 9 divide both sides by 3
[ 4 - 5x l = 3
Note that we have that either
4 - 5x = 3 or that 4 - 5x = -3
Subtract 4 from both sides
-5x = -1 -5x -7
Divide both sides by -5
x = 1/5 x = 7/5
Our solution will either lie on [ 1/5, 7/5 ] or outside of this interval
Test an x value outside this interval in the original inequality to see if it makes the inequality true, or not.....I'll pick 0
3 l 4 - 5(0) l ≤ 9
3 l 4 l ≤ 9
12 ≤ 9
This is false......so.....the solution comes from [ 1/5, 7/5 ]
Both endpoints are included because of the " ≤ " sign
