v = <3,0,0> and w = <0,1,-1> Determine u = v x w using the geometric properties of the cross product rather than the formula.
The cross-product gives a vector (in this case u), which is orthogonal to both v and w.
i.e. u is normal to the plane that v and w lie on, and also has the same coefficients as that plane.
So find the plane that v and w lie on, and then you have the normal, and so you have the cross product.