this is my notebook. I wanna get the max{3 x1 + 6x2 + 14x3 + 25x4 + 54x5 + 164x6 + 324x7 + 499x8 + 2000x9 + 13x10 + 10x11 + 20x12 + 10x13 + 20*x14} the condition: {x1...x10}>=0 2>x11>=0 2>x12>=0 2>x13>=0 2>x14>=0 and 18>6x1+12x2+28x3+50x4+108x5+328x6+648x7+998x8+1998x9+2x10+8x11+15x12+18x13+30x14>=6 the mathematicas only reduce Thanks
NMaximize[{3 x1 + 6*x2 + 14*x3 + 25*x4 + 54*x5 + 164*x6 + 324*x7 +
499*x8 + 2000*x9 + 13*x10 + 10*x11 + 20*x12 + 10*x13 + 20*x14,
18 > 6*x1 + 12*x2 + 28*x3 + 50*x4 + 108*x5 + 328*x6 + 648*x7 +
998*x8 + 1998*x9 + 2*x10 + 8*x11 + 15*x12 + 18*x13 + 30*x14 >= 6,
x1 >= 0, x2 >= 0, x3 >= 0, x4 >= 0, x5 >= 0, x6 >= 0, x7 >= 0,
x8 >= 0, x9 >= 0, x10 >= 0, 2 > x11 >= 0, 2 > x12 >= 0,
2 > x13 >= 0, 2 > x14 >= 0}, {x1, x2, x3, x4, x5, x6, x10, x11, x12,
x13, x14}, Integers]