Please help in factorising this polynomial.

y = 2x^3 - x^2 - 8x + 4

alsox + 2is a factor

i used the remainder theorem and then long divided the equation

and i ended up with..

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

help? lol

many thanks

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- Apr 5th 2006, 01:16 PMraidenFactorising
Please help in factorising this polynomial.

**y = 2x^3 - x^2 - 8x + 4**

also**x + 2**is a factor

i used the remainder theorem and then long divided the equation

and i ended up with..

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

help? lol

many thanks - Apr 5th 2006, 06:56 PMThePerfectHackerQuote:

Originally Posted by**raiden**

Anyways,

You have,

$\displaystyle 2x^3-x^2-8x+4$

Group terms as,

$\displaystyle (2x^3-8x)-(x^2-4)$

Factor,

$\displaystyle 2x(x^2-4)-(x^2-4)$

Factor again,

$\displaystyle (x^2-4)(2x-1)$

Factor again,

$\displaystyle (x+2)(x-2)(2x-1)$