You are Here: Home >< Maths

# C3 remainder theorem Watch

1. divide x³+x²-7 by x-3

help pls
2. (Original post by Big white)
divide x³+x²-7 by x-3

help pls
Do you know how to do long division?
3. (Original post by Zacken)
Do you know how to do long division?
yes and i can do that but the question states i must use remainder theorem
4. (Original post by Big white)
yes and i can do that but the question states i must use remainder theorem
Pretty sure they're all the same thing?
5. (Original post by Zacken)
Pretty sure they're all the same thing?
here what are they doing at the bit where they say compare coefficients because i don't understand what they've done
Attached Images

6. (Original post by Big white)
here what are they doing at the bit where they say compare coefficients because i don't understand what they've done
They're comparing coefficients.

So the coefficient of x^3 on the LHS is the same as the coefficient of x^3 on the RHS, etc...
7. (Original post by Zacken)
They're comparing coefficients.

So the coefficient of x^3 on the LHS is the same as the coefficient of x^3 on the RHS, etc...
but why A=1? why not any other number?
8. (Original post by Big white)
but why A=1? why not any other number?

The coefficient of x^3 on the LHS (left hand site of the equality) is 1. x^3 = 1 * x^3. The coefficient is one, it's 1.

The coefficient of x^3 on the RHS (right hand side of the equality) is A.

The coefficients of x^3 on both sides has to be the same.

So A and 1 have to be the same, this is abbreviated to A = 1.
9. (Original post by Zacken)

The coefficient of x^3 on the LHS (left hand site of the equality) is 1. x^3 = 1 * x^3. The coefficient is one, it's 1.

The coefficient of x^3 on the RHS (right hand side of the equality) is A.

The coefficients of x^3 on both sides has to be the same.

So A and 1 have to be the same, this is abbreviated to A = 1.
Ohhhhhhhhh right i see. but you can only do that for the x³ coefficient?
10. (Original post by Big white)
Ohhhhhhhhh right i see. but you can only do that for the x³ coefficient?
No, you can do that for the x^2 coefficient and of the x^1 coefficient, and for the x^(35345345345345) coefficient.
11. (Original post by Zacken)
No, you can do that for the x^2 coefficient and of the x^1 coefficient, and for the x^(35345345345345) coefficient.
ok so i understand now thanks
12. (Original post by Big white)
ok so i understand now thanks
Great!
13. (Original post by Zacken)
Great!
DO you know if you need to know how to do the comparing coefficients thing for c3 edexcel can you just do long division?
DO you know if you need to know how to do the comparing coefficients thing for c3 edexcel can you just do long division?
Just using long division is fine.

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: July 3, 2017
Today on TSR

### Anxious about my Oxford offer

What should I do?

### Am I doomed because I messed up my mocks?

Discussions on TSR

• Latest
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• 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
• ## See more of what you like on The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

• 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