x Turn on thread page Beta
 You are Here: Home >< Maths

# Polynomials watch

1. the cubic polynomial 2x^3-5x^2+ax+b is denoted by f(x). It is given that (x-2) is a factor of f(x),and that when f(x) is divided by (x-1) the remainder is -6. find the values of a and b.
2. (Original post by TumiZN)
the cubic polynomial 2x^3-5x^2+ax+b is denoted by f(x). It is given that (x-2) is a factor of f(x),and that when f(x) is divided by (x-1) the remainder is -6. find the values of a and b.
Any ideas? Do you know the factor theorem?
3. (Original post by TumiZN)
the cubic polynomial 2x^3-5x^2+ax+b is denoted by f(x). It is given that (x-2) is a factor of f(x),and that when f(x) is divided by (x-1) the remainder is -6. find the values of a and b.
use the factor/remainder theorem and set 2 simultaneous equations
4. (Original post by notnek)
Any ideas? Do you know the factor theorem?
In class doing the question is easy but once at home it is as though a part of my brain shuts off
5. (Original post by TumiZN)
In class doing the question is easy but once at home it is as though a part of my brain shuts off
Ok I'll start you off:

If (x-2) is a factor of f(x) then this means that f(2) must be equal to 0.

To find f(2), you need to substitute 2 into 2x^3-5x^2+ax+b. Then set this to 0.

If (x-1) divided gives a remainder of -6 it means that f(1) = -6.

Have a go at this now and post all your working if you get stuck - it doesn't matter if your working is wrong.
6. (Original post by notnek)
Ok I'll start you off:

If (x-2) is a factor of f(x) then this means that f(2) must be equal to 0.

To find f(2), you need to substitute 2 into 2x^3-5x^2+ax+b. Then set this to 0.

If (x-1) divided gives a remainder of -6 it means that f(1) = -6.

Have a go at this now and post all your working if you get stuck - it doesn't matter if your working is wrong.
Thank you , you made it easier to understand

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 25, 2016
Today on TSR

### Happy St Patrick's day!

How are you celebrating?

### Stay at sixth form or go to college?

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