The task is to generate the correct answer for a given math problem.
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Question: Problem: if 1 / ( x + 4 ) + 1 / ( x - 4 ) = 1 / ( x - 4 ) , what is the value of x ?

Answer: 4


Question: Problem: a contractor undertook to do a piece of work in 18 days . he employed certain number of laboures but 9 of them were absent from the very first day and the rest could finish the work in only 6 days . find the number of men originally employed ?

Answer: 4.5


Question: Problem: if 9 a - b = 10 b + 50 = - 12 b - 2 a , what is the value of 11 a + 11 b ?

Answer:
0