Matlab

Syms x1;
Eqn=3.381 * log (x1) x1 + 0.1038 + 0.142 * * x1 ^ 2 x1==^ 3-1.3807-0.017 *;
T2=solve (eqn);
Disp (T2);

The output is 4.5793238855711022310996618304163 + 5.7869600105293274945234158264147 I

For bosses to help have a look at why did such a number, the normal equation is arguably should be 0.6395