You would distribute the -6 on one side and the 7 on the other.
[tex] - 6x + 24 < 14x - 21[/tex]
Then you would move the 24 to the other side, by subtracting.
[tex] - 6x < 14x - 45[/tex]
Then you would move 14x to the other side by subtracting
[tex] - 20x < - 45[/tex]
Then divide by -20 to get x by itself. You would have to flip the sign, since you divided by a negative.
[tex]x > 2.25[/tex]