You are Here: Home >< Maths

# 2x − 1 < 3x + 2  watch

1. The cubes in the title are abs value signs
My working out is:
Spoiler:
Show
2x-1>-3x-2
5x>-1
x>-1/5

2x-1<3x+2
-3<x x>-3 x>-1/5
The solution is:
Spoiler:
Show
x < −3 or x > -1/5
Why is the x<-3 sign that way around, I thought if you divide by a negative the sign flips?
2. (Original post by TheGreatPumpkin)
The cubes in the title are abs value signs
Why is the x<-3 sign that way around, I thought if you divide by a negative the sign flips?
You have to be a bit careful with modulus inequalities, just like solving quadratic inequalities is different to solving quadratic equations.

I would definitely recommend drawing a graph. You have two simple linear graphs so it shouldn't be hard to sketch them and see what's going on.

This video deals with a similar problem and shows you two methods you can use.

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: October 30, 2016
The home of Results and Clearing

### 1,068

people online now

### 1,567,000

students helped last year
Today on TSR

### University open days

1. Sheffield Hallam University
Tue, 21 Aug '18
2. Bournemouth University
Wed, 22 Aug '18
3. University of Buckingham
Thu, 23 Aug '18
Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams