Would Adam and Eve have lived forever if they didn't eat from the tree of the knowledge of good and evil?
"but you must not eat from the tree of the knowledge of good and evil, for when you eat from it you will certainly die." Genesis 2:17
Yes according to some. The Stone edition of the Chumash reads, "Since Adam lived to the age of 930, it was clear that he was not to die as soon as he ate the fruit. Rather, he would become subject to death, whereas if he had never sinned, his holiness would have kept him alive forever." This statement lacks any attribution.
The Ramban seems to say that death is a natural consequence of being alive and the text's statement is that by eating the fruit, man became chayav a death sentence for having committed a crime. Death became a punishment, not a normal part of the existence process.