>

?solve

>	solve({x+y=1,x=2},{x,y});

>	solve({c+0.1*s+0.1*f=10000,0.05*c+s=5000,0.4*c+0.4*s+f=40000},{c,s,f});

>	solve({c+0.1*s+0.1*f=10000,0.05*c+s+0.05*f=5000,0.4*c+0.4*s+f=40000},{c,s,f});

>	with(linalg);

>

?matrix

>	?gaussjord

>	?gausselim

>	B:=linalg[matrix](3,4,[1,0.1,0.1,10000,0.05,1,0.05,5000,0.4,0.4,1,40000]);

>	gausselim(B);

>	gaussjord(B);

>	A:=linalg[matrix](3,3,[1,0.1,0.1,0.05,1,0.05,0.4,0.4,1]);

>	inverse(A);

>	multiply(A,inverse(A));

>	c:=linalg[matrix](3,1,[10000,5000,40000]);

>	multiply(inverse(A),c);

>	with(plots);

Warning, the name changecoords has been redefined

>	plot1:=plot3d(-0.1*s-0.1*f+10000,s=0..5000,f=0..40000,axes=boxed):

>	plot2:=plot3d(100000-20*s-f,s=0..5000,f=0..40000,axes=boxed):

>	plot3:=plot3d(100000-s-2.5*f,s=0..5000,f=0..40000,axes=boxed):

>	display(plot1);

>	display(plot1,plot2,plot3);

>