ex7
11x 4+11x4=88 2x11+3x4+3x4=46 10x11+9x4+9x4=182
11x 4+11x4+25=113 11x 4+11x4-34=54 7x4+7x4+9x11=155
11x 4+11x4-6x11=22 3x11-3x4-3x4=9 11x4+11x4=88
ex 8
14x23+14x23+14x23 x9=3542 2013-(53x23+53x23+53x23+10x9)=-1734
349+6x23+6x23+6x23-12x9=673 424-21x9+3x23+3x23+3x23=373
7x23+7x23+7x23-10x9=393
3147-10x9-(100x23+100x23+100x23)=-1238853
