Look at the inequality 18-ax>4

Question

Look at the inequality 18-ax>4

 

Let a be a negative number, which inequality must be  true?

 

* x<14/a

* x<14a

* x>14/a

* x>14a

Answer 1

18 - ax > 4

 

-ax > -14       divide both sides by a. Because a is a negative number, reverse the inequality

 

-x < -14/a       multiply both sides by -1. Again reverse the inequality.

 

x > 14/a

 

answer C

 

It could also be done as follows but I think the first way is clearer.

 

18 - ax > 4

 

-ax > -14      divide by -a which is a positive value because a is negative

 

x > -14 / -a

 

x > 14/a