To prove that T(0) = 0 for a linear transformation T: V -> W, it is essential to recognize that T can be expressed in terms of a transformation matrix A, where T(v) = Av. The transformation must adhere to the properties of linearity, specifically that T(u + v) = T(u) + T(v) and T(au) = aT(u). By applying these properties, substituting v with the zero vector or a with zero demonstrates that T(0) must equal 0. Thus, the proof confirms that linear transformations map the zero vector to the zero vector.