Solution 2.1:1c
From Förberedande kurs i matematik 1
(Difference between revisions)
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The factor <math> -x^2 </math> can be written as <math>(-1)x^2 </math> and both factors can be multiplied into the bracket: | The factor <math> -x^2 </math> can be written as <math>(-1)x^2 </math> and both factors can be multiplied into the bracket: | ||
- | + | <math> | |
+ | \qquad | ||
+ | \begin{align} | ||
+ | -x^2 (4-y^2) &= (-1)x^2(4-y^2) \\ | ||
+ | &= (-1)x^2 \cdot 4 - (-1)x^2 \cdot y^2 \\ | ||
+ | &= -4x^2 +x^2 y^2. | ||
+ | \end{align} | ||
+ | </math> | ||
{{NAVCONTENT_STOP}} | {{NAVCONTENT_STOP}} |
Revision as of 08:48, 13 August 2008
The factor \displaystyle -x^2 can be written as \displaystyle (-1)x^2 and both factors can be multiplied into the bracket:
\displaystyle \qquad \begin{align} -x^2 (4-y^2) &= (-1)x^2(4-y^2) \\ &= (-1)x^2 \cdot 4 - (-1)x^2 \cdot y^2 \\ &= -4x^2 +x^2 y^2. \end{align}