1 votes 1 votes here nothing is given whether language is decidable or not.so how to solve it Theory of Computation bad-question + – Vineeta Garg asked Dec 27, 2016 Vineeta Garg 375 views answer comment Share Follow See all 3 Comments See all 3 3 Comments reply Kapil commented Dec 27, 2016 reply Follow Share Question says can be valid not always valid 1 votes 1 votes vijaycs commented Dec 27, 2016 reply Follow Share @Kapil, option B can also be true .. right ??If L, L2, L2 are RE ( undecidable ) ?? 1 votes 1 votes Kapil commented Dec 27, 2016 reply Follow Share Yes, again MAY BE when all the languages are not even RE. 1 votes 1 votes Please log in or register to add a comment.