20.) let v and w be vector spaces with subspaces vi and wi, respectively if t: v - w is linear, prove that t(v1) is a subspace of w and that rev: t(æ) e w} is a

20.) Let V and W be vector spaces with subspaces Vi and Wi, respectively If T: V - W is linear, prove that T(V1) is a subspace of W and that rEV: T(æ) E W} is a subspace of V.