If rank(XY) = rank(X), show that the column space C(XY) = C(X)

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My attempt:

rank(XY) = dim(C(XY))

rank(X) = dim(C(X))

Therefore, dim(C(XY)) = dim(C(X))

Therefore, C(XY) is a subset of C(X)

Therefore, C(XY) = C(X)