Question 606451
If y=2x^3+18x^2-20 for 0≤x≤10, the maximum value of y occurs when x=

A) 0
B) 1.13
C) 6
D) 8.87
E) 10

I, naturally, believed the answer to be 10, as it is the largest choice, resulting in a value of 3780 for y.

But the explanation says otherwise:

Choice (C) is the correct answer to question 3.  You can use a graphing calculator to help you solve the problem.  Graph the equation in an appropriate viewing window that allows you to see the maximum value of Y.  You can do this by setting the values of x from 0 to 10 and then selecting a zoom option that fits the y-values for the given x-values.  Once you graph the equation, use the "maximum" feature of the calculator to find the maximum value of y on the interval 0≤x≤10.  You can see from the graph that the max value of y is 196, which occurs when x=6.  It is important to remember that the minimum or maximum values do not have to occur at the endpoints of the domain interval. 

When I plugged 6 into the equation, I got 1060, not 196.  What's more, that's not the largest value of y; 3780 is.  Why is the answer 6?  Is this a misconception on my part? As far as I know, maximum means the largest value.  As in, which value of x results in the largest value of y.  
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Of the choices given, 10 is correct.
f(6) < f(10)
There is a local max at x = -6, but that's not in range of 0 to 10.
I suspect a typo somewhere.