Hi,
i need help with problems i have atthached...
Use the properties you know. Scalar multiplication is commutative and associative. So $\displaystyle A(kX_0) = A(X_0k) = (AX_0)k = 0k = 0$.
Matrix multiplication is left distributive: $\displaystyle A(kX_0+X_1) = (AkX_0) + AX_1 = 0+C = C$.