Work Shown:
5x - 14x < - 18
-9x < - 18
x > -18/(-9)
x > 2
The inequality sign flips when dividing both sides by a negative number.
Here's another approach you could take.
5x - 14x < - 18
-9x < -18
0 < -18+9x
18 < 9x
9x > 18
x > 18/9
x > 2
It's a slightly longer pathway, but it avoids a sign flip when you divide both sides by the positive number 9.
The sign flip happens two steps earlier when going from 18 < 9x to 9x > 18. In other words, A < B is the same as B > A.
