Help solve maths question... (1 Viewer)

[Brodie28]

How do I factorise this?

(x+1)(3x³+8x²+7x+2)

Iv tried a few ways but cant seem to get the right answer...

 

[rama_v]

Use polynomial division. I think this is a 3 unit question, Im not sure of how you would do it without using polynomial division...but it simplifies to (x+1)³(3x+2)

Edit: have a look at KFunks solution in the extension forum.

 

[Kutay]

thats a 3 unit concept yeh, sorta like got to do long division


___________________
x + 1 | 3x^3 + 8x^2 + 7x + 2


by doing that you get:

( x + 1 ) ( 3x^2 + 5x + 2)

which then factors to:

(x + 1) (3x + 2) (x + 1)

sorry couldn't show the working out in the division i just dont know how to on the computer and anyhow i think this is a more area you touch in extension 1

 

[zenger69]

eh... it's not a 2u question.

substitute numbers divisible by 2

ie. x = 2
x = -2
x = 1
x = -1

if one of them equals zero, therefore it's a factor (if it's x=1 then (x-1) is a factor).

I would divid the cubic by the factor (ie (x-1). which is a 3u concept.