inequality (1 Viewer)

a little lost

relationships pfft
Joined
Oct 11, 2003
Messages
94
can someone answer the question for me i'm just lost
its an inequality question
5/x+2< or equal to one?

i just uploaded the answer.
my question is why does the sign change during the working out
 

a little lost

relationships pfft
Joined
Oct 11, 2003
Messages
94
ok i didn't upload well the question is why does the sign change during the working out?
 

PoLaRbEaR

The Bear
Joined
Apr 13, 2003
Messages
253
Location
Sydney
Gender
Male
HSC
2003
5(x+2) < (x+2)^2
(x+2)^2 - 5(x+2) > 0
That's probably the way you've got it...just moving the 5(x+2) to the other side...
 

Rahul

Dead Member
Joined
Dec 14, 2002
Messages
3,647
Location
shadowy shadows
becasue you cant multiply by a negative without changing the sign and since you dont know whether x is one or not, you should multiply both sides by (x+2)^2. this way you know that you are multiplying by a positve, since A^2>0. after doing that just factorise.
 

bMaN oNe

Member
Joined
Oct 14, 2003
Messages
31
Location
Sydney
Gender
Male
HSC
2003
once u get to this point:
x(x+5) <= 0
draw a little graph of this parabola (intercepts 0 and -5)
then look at the graph, and see where the graph is <= 0, and whoala u get the answer...
Oh wait, is that 5/(x+2) or 5/x + 2?
If its the first one forget wot i posted ;)
 
Last edited:

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top