f=@(x,y,z) 2*x+y+z+10;
x=linspace(-8,8,21);
y=linspace(-8,8,20);
z=linspace(-8,8,20);
plot3(0,0,0)
hold on
[X,Y,Z] = meshgrid(x,y,z);
clf
isosurface(X,Y,Z,f(X,Y,Z),14)
f=@(x,y,z) 3*x-y+2*z;
[X,Y,Z] = meshgrid(x,y,z);
isosurface(X,Y,Z,f(X,Y,Z),1,'g')
axis equal 
%alpha(0.3)
colormap copper
grid
rotate3d