You are Here: Home >< Maths

# Difference between two squares maths question watch

1. the question is: Prove that (3x+1)^2 - (3x-1)^2 is a multiple of 4, for all positive integer values of x.
I've tried so many times to figure this out but I just can't. I already know what the answer is, but I can't follow the process. If someone could go through it in detail I'd be grateful.
2. (Original post by warmmuffin)
the question is: Prove that (3x+1)^2 - (3x-1)^2 is a multiple of 4, for all positive integer values of x.
I've tried so many times to figure this out but I just can't. I already know what the answer is, but I can't follow the process. If someone could go through it in detail I'd be grateful.
expand the brackets, answer should be clear after that
3. (3x + 1)^2 - (3x - 1)^2 = (3x + 1 + 3x - 1)(3x + 1 - 3x + 1)
Use this.

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: January 10, 2015
Today on TSR

### The most controversial member on TSR?

Who do you think it is...

### Is confrontation required?

Discussions on TSR

• Latest
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

## Groups associated with this forum:

View associated groups
Discussions on TSR

• Latest

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE