Question

Cubic help

Answer 1

Graph doesn't look very cubic to me though which makes me thing I did it wrong.

Answer 2

what's the exact question?

Answer 3

as in what is the exact wording of the question you're trying to answer.
positive rate of change → function is increasing
negative rate of change → function is decreasing

Answer 4

Is it possible to post an image of the original question?
That's the fastest way to get help!

Answer 5

You're giving a lot of information, but there's no context

Answer 6

So I can do cubic regression or do l*w*h where (12-x) represents the sides and (x) represents the height of the boxes... whichever one you guys are able to help me with.

Answer 7

Kinda wanted to know how to do it by hand, but maybe that isn't good to know as a pre-algebra student.

Answer 8

Hints:
"where (12-x) represents the sides and (x) represents the height of the box)"
means:
So if the height (x)=1, then the sides are (12-1)=11, or 1*11*11, V=121
If height is 2, sides are 12-2=10, volume = 2*10*10=200
in general, if the height equals x, the volume is x(12-x)(12-x), which is evidently a cubic.
Do you agree with the above calculations?

Answer 9

Yeah that makes sense.

Answer 10

Yes, a cubic is a polynomial, which is any expression in the form of "the sum of positive integer powers of a variable, each multiplied by a constant".

Answer 11

I do not know how you got
y=-12x^2 + 49.6x + 67.2
but the volume itself is already a cubic (third degree polynomial), and will not need to have a cubic regression, because it is exactly a cubic polynomial.

Answer 12

But your table does not correspond to the given constraints of x=height, (12-x)=sides, so it cannot be used to "generate" your regression cubic.

Answer 13

But your table does not correspond to the given constraints of x=height, (12-x)=sides, so it cannot be used to "generate" your regression cubic that represent the results of the problem.

Answer 14

But if it's wrong then I will just go with the way you showed me.

Answer 15

In your table, I do not understand what you meant by "size of corner cut ". I use x=height, as per instructions.

Answer 16

size of corner cut meants (remember I used grid paper to make cubes) I had to cut off one square on each corner. Let me draw it for you okay. I'm really sorry for confusing you. I did a very bad job explaining everything.

Answer 17

Give me a few minutes. please.

Answer 18

So that means the height.