SOLUTION: Show without expanding that x = 2 is a root of the equation | x -6 -1 | | 2 -3x x - 3| ==0 and solve it completely. |-3 2x x + 2|

Question 969027: Show without expanding that x = 2 is a root of the equation
| x -6 -1 |
| 2 -3x x - 3| ==0 and solve it completely.
|-3 2x x + 2|

Answer by Edwin McCravy(20056) (Show Source): You can put this solution on YOUR website!
Show without expanding that x = 2 is a root of the equation

 and solve it completely.

Substitute x=2 in the determinant


 



The first two rows are the same, so if you subtract
the second row from the top row you get



If this were expanded about the top row, all the minors
would be multiplied by 0 giving 0.

Edwin

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