The next step is the backward substitution step. The last row is multiplied by \( c_{N-3}/b_{N-2} \) and subtracted from the second to last row, thus eliminating \( c_{N-3} \) from the last row. The general backward substitution procedure is

$$ c_i = 0, $$

and

$$ f_{i-1} = f_{i-1} - \frac{c_{i-1}}{b_i}f_i $$

All that ramains to be computed is the solution, which is the very straight forward process of

$$ x_i = \frac{f_i}{b_i} $$