-1/2X > 2x+5

Work it like an equation, but if you multiply the inequality by a negative number, reverse the direction of the inequality sign.

-1/2X > 2x+5
-(1/2)x -2x > 5
-(5/2)x > 5 (now multiply by -(2/5)
x < 5*(-2/5)
x< -2