Question 666136
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Hi,
y = x^3 - 10.5x^2 + 30x +20
y' = 3x^2 - 21x + 30
When Slope = 0, maxima and minina pts are achieved at x.
 3x^2 - 21x + 30 = 0
  x^2 - 7x + 10 = 0
 (x-2)(x-5) = 0  x = 2 or x = 5
f(2) = 46   maxima
f(5) = 32.5 minima