7x (33y+9z) - 3x (9y-2z+13b) =
Simple answer #1!
3x (-13 b+68 y+23 z), Root: x=0
I think this is the right answer, atleast this is what the calculator gave me...
-39bx+204xy+69xz
Yes. that's the "Derivative":
(d)/(dx)(7 x (33 y+9 z)-(3 x) (9 y-2 z+13 b)) = -39 b+204 y+69 z
