Question 612687
A is a 3x3 matrix 
A= 
[a,  3, 4]
[a, -3, 8]
[8,  4, a]
find all values of |A|=0.
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Equation:
-3a^2 +16a + 192 - (-96+32a+3a^2) = 0
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-3a^2-3a^2 + 16a - 32a + 96 +192 = 0
-6a^2 - 16a + 288 = 0
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3a^2 + 8a - 144 = 0
a = 5.722 or x = -8.389
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Cheers,
Stan H.