# How to solve a simple B-spline with table function?

Determine the natural cubic B-spline for a function in a table form of:

$$x_i\|-1\|0\|1\|2 \\ y_i\|-3\|0\|1\|2$$

So I'm very new to cubic splines and am quite lost on what I should do. I know I should express every point as a function of form $a_ix^3+b_ix^2+c_ix+d_i$ and then solve a system of equations with all of them but how am I supposed to show a pair like $(-1, -3)$ in such a form? I mean: aren't there infinitely many ways of doing it?

Any guidance on how to advance would be welcome :)

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