Quote: what is the answer to -5/2x>30?
-5/2x > 30
-5/2x results in a problem at x=0:
so let's see the plot:
[input]plot( -5/(2x) , 30, x= -1..1, -10..40 )[/input]
as you can see, for all x>0 the result of -5/2x will be less than zero.
for x < 0:
-5/(2x)
x in the denominator, so try the reciprocal value: (switch > to <)
-5/2x > 30
| reciprocal (2x)/-5 < 1/30
(2x) < -5/30
|*(-5) x > -5/60
|/2 x > -1/12
so the result is:
-1/12 < x < 0
+3146 
