Solution 2.3:5c
From Förberedande kurs i matematik 1
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- | If | + | If <math>x=1</math> is a root of the equation, the equation should be satisfied if we substitute in <math>x=1</math> into it, i.e. <math>1^{2}+4\cdot 1+b=5+b</math> should be equal to zero, and this gives directly that <math>b=-5\,</math>. |
- | <math>x= | + | |
- | is a root of the equation, the equation should be satisfied if we substitute in | + | |
- | <math>x= | + | |
- | into it, | + | |
- | + | ||
- | i.e. | + | |
- | + | ||
- | <math>1^{2}+4\ | + | |
- | should be equal to zero, and this gives directly that | + | |
- | <math>b=-\ | + |
Current revision
If \displaystyle x=1 is a root of the equation, the equation should be satisfied if we substitute in \displaystyle x=1 into it, i.e. \displaystyle 1^{2}+4\cdot 1+b=5+b should be equal to zero, and this gives directly that \displaystyle b=-5\,.