Linear Algebra: How do I solve span and linearly independent vector space?

ume that in a vector space V, both the set (u1, u2) and the set (w1, w2) are linearly independent. Further ume that span (u1, u2) intersection symbol (w1, w2) = 0. Prove that the set (u1,u2,w1,w2) is linearly independent.