MAXIMA 
zadanie 1 
kod:

eq1: 2*x-2*y+z-w=7;
eq2:-x +4*y-5*z+3*w = 1;
eq3: x +y-z+w = 4;
eq4:-4*x + 2*y +  z - 2*w = 6;

linsolve([eq1,eq2,eq3,eq4] , [x,y,z,w ]);


zadanie2
solve(x^3-21*x+20=0);


zadanie3
h1(x):= x^2-2*x+3;

plot2d(h1,[x,-4,5],[color,blue]);

zadanie4

h1(x):= cos(2*x);


plot2d(h1,[x,-4,5],[color,red]);
zadanie5
h1(x):= sin(1/x);


plot2d(h1,[x,-4,5]);
zadanie6

f(x,y):= x^2+y^2;


plot3d(f(x,y),[x,-2,2],[y,-2,2]); 
zadanie7
f(x,y):= x^2-y^2+2*x*y^2+1;


plot3d(f(x,y),[x,-2,2],[y,-2,2]);