Question 557167
Determine the abscissae of the maxima, minima and inflection points. 
y = x^4 + 6x^3 - 5
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y' = 4x^3 + 18x^2 = 0
--> min @ x = -9/2
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y'' = 12x^2 + 36x = 0
--> inflections @ x = 0, -3
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The answer is supposed to be: Minimum at x point = -9/2, inflection points at x=0 and x=-3