Ok so I need help finding out how you write cubic expressions just from looking at the graph.

The problem is that it's a strange cubic that cuts through the y-axis at 6.

I'm not sure how to ask this question but all I can give you is the answer of the graph in it's expression.

So the curve it shows in the paper starts from the point 6 on the y-axis and then comes down to 2 on the x-axis where it touches the x-axis and then goes up and down again through 5 at the x-axis.

The only thing that boggles me is the 0.3, the one number that acts on the whole equation causing it to cut through the y-axis at 6.

It also states that the length of the object is 6m

That's the most detail I can provide into this question. Help would be awesome, thank you.