Prob. 39, Chap. 7, in Schaum's GENERAL TOPOLOGY: The images of sets of a basis of the domain space under an onto open map ...

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Let $(X, \mathscr{T})$ and $\left(Y, \mathscr{T}^*\right)$ be topological spaces, let the function $f \colon (X, \mathscr{T}) \longrightarrow \left(Y, \mathscr{T}^*\right)$ be open and onto, and let $\mathscr{B}$ be a basis for $\mathscr{T}$. Then how to show that the collection $$ \big\{ f(B) \colon B \in \mathscr{B} \big\} \tag{0} $$ is a basis for $\mathscr{T}^*$?

My Attempt:

Let $V$ be any open set in $\left( Y, \mathscr{T}^* \right)$. We need to show that $V$ can be expressed as a union of some sets in the collection (0) above.

Since $f$ is onto, we have $$ V = f \left( f^{-1}(V) \right). $$

And, since $f$ is open, each set $f(B)$ in the collection (0) above is also an open set of $\left(Y, \mathscr{T}^* \right)$.

How to proceed from here?