Question

-10x < 40

Answer 1

A. x < -4 B. x < 4 C. x > -4 D. x > 4

Answer 2

You need to divide both sides of the equation by -10. By doing so, since it's negative, the inequality sign will switch, going from < to >, so you'll left with this :
-10x/-10 > 40/-10
x > 4

Answer 3

and you can validate that, if x = 5, you'll get -10 * 5 = -50, which is smaller than -40