Help a Noob...

New to chess, still learning. I must be missing something obvious. Enlighten me! <3

I was given this puzzle. The initial move is Bxb3. (a white bishop was taken)

The "solution" was one move, Rxe8#. (Taking the black rook)

How can this be checkmate if the king could just recapture the unsupported rook? It is supported by a second rook on F8 too.  In order for checkmate, doesn't the rook need to be protected by another white piece? There is some coverage from the c7 pawn and the f6 queen, but nothing for the e8 rook. (that I see)

Thanks for any insight. 

This is chess

We don't use 'Noob', we use 'Beginner' or 'Novice' or 'Intermediate'

It isn't checkmate directly i.e. it's not Rxe8#, it's Rxe8+
The king has to capture the rook and then one solution is that Qd8# is checkmate, or another solution is c8=Q# (pawn promotion).



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