Pentru a obtine 100 de puncte trebuie gasita o metoda mai eficienta de a rezolva aceasta recurenta, lucru realizabil prin transpunerea ei in matrici in felul urmator:

*Nu imi merge sa fac matricile in latex, imi da eroarea asta:" Warning: Cannot modify header information - headers already sent by (output started at /home/infoarena/live/www/views/header.php:98) in /home/infoarena/live/common/log.php on line 309 "

<tex>\[ \left( \begin{array}{cccc}1 & -2 & -7 & 0 \\9 & 2 & -6 & 2 \\-4 & 1 & -4 & 1 \\-1 & 8 & 0 & -2 \end{array} \right)\]</tex>