Processing Math: Done
Solution 2.1:1e
From Förberedande kurs i matematik 1
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Revision as of 08:31, 9 September 2008
If we use the rule for squaring
(x−7)2=x2−2 x
7+72=x2−14x+49
An alternative is to write the square as (x−7)
(x−7)=(x−7)
x−(x−7)
7=x
x−7
x−(x
7−7
7)=x2−7x−(7x−49)=
x2−7x−7x+49=x2−(7+7)x+49=x2−14x+49
In the line that has been marked with an asterisk, we have removed the bracket and at the same time changed signs on all terms inside the bracket.