From Förberedande kurs i matematik 1

Revision as of 09:54, 31 March 2008 (edit) Lina (Talk | contribs) (Ny sida: {{NAVCONTENT_START}} <center> Bild:2_1_3e.gif </center> {{NAVCONTENT_STOP}}) ← Previous diff		Current revision (08:37, 23 September 2008) (edit) (undo) Tek (Talk | contribs) m
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-	{{NAVCONTENT_START}}	+	Both terms contain ''x'', which can therefore be taken out as a factor (as can 2),
-	<center> [[Bild:2_1_3e.gif]] </center>	+
-	{{NAVCONTENT_STOP}}	+	{{Displayed math||<math>18x-2x^3=2x\cdot 9-2x \cdot x^2=2x(9-x^2)\,\textrm{.}</math>}}
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		+	The remaining second-degree factor <math> 9-x^2 </math> can then be factorized using the conjugate rule
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		+	{{Displayed math||<math> 2x(9-x^2)=2x(3^2-x^2)=2x(3+x)(3-x)\,,</math>}}
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		+	which can also be written as <math>-2x(x+3)(x-3).</math>

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Current revision

Both terms contain x, which can therefore be taken out as a factor (as can 2),

\displaystyle 18x-2x^3=2x\cdot 9-2x \cdot x^2=2x(9-x^2)\,\textrm{.}

The remaining second-degree factor \displaystyle 9-x^2 can then be factorized using the conjugate rule

\displaystyle 2x(9-x^2)=2x(3^2-x^2)=2x(3+x)(3-x)\,,

which can also be written as \displaystyle -2x(x+3)(x-3).