Gather Toward the Larger

5 - x < 2x - 4: the x-terms are -x on the left and 2x on the right. Gathering them on the right, where the coefficient is larger, keeps the coefficient positive and avoids a flip. Add x to both sides:

5 < 3x - 4

9 < 3x

3 < x

which reads x > 3.

Gathering on the left instead would give -3x < -9 and then a division by -3 with a flip: x > 3 again. Both routes are right. Gathering toward the larger coefficient is simply the route with no flip to remember, and the finishing swap costs nothing.