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Mathematics-Online lexicon:

Factor out


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z overview

An equation of the form

$\displaystyle a_nx^n+a_{n-1}x^{n-1}+...+a_{n-m+1}x^{n-m+1}+a_{n-m}x^{n-m}=0 \textnormal{, } \qquad a_n\not=0 \qquad n>m
$

can be solved by factoring out the smallest power $ x^{n-m}$ that occurs in the term.

$\displaystyle x^{n-m}(a_nx^{m}+a_{n-1}x^{m-1}+...+a_{n-m+1}x+a_{n-m})=0 \textnormal{, } \qquad a_n\not=0
$

As a product is zero iff at least one the factors is zero, you get the ($ n-m$)-fold solution of the equation

$\displaystyle x=0.
$

The further $ m$ solution can be calculated by solving the term in the brackets

$\displaystyle a_nx^{m}+a_{n-1}x^{m-1}+...+a_{n-m+1}x+a_{n-m}=0.
$

(Authors: Jahn/Knödler)

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  automatically generated 7/ 8/2004