Question 321813
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*[tex \LARGE \ \ \ \ \ \ \ \ \ \ \left|x\,-\,1\ \ \ \ 1\cr\ \ \cr-9\ \ \ x\,-\,7\right|\ =\ (x\,-\,1)(x\,-\,7)\ -\ (-9)(1)\ =\ x^2\ -\ 8x\ +\ 16]


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ x^2\ -\ 8x\ +\ 16\ =\ 0]


You can take it from here.


John
*[tex \LARGE e^{i\pi} + 1 = 0]
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