To simplify the expression 5 11/41 - 2 3/14 - 11/21, we need to first convert each mixed number to an improper fraction.

5 11/41 = (5 41 + 11)/41 = 256/41
2 3/14 = (2 14 + 3)/14 = 31/14

Now, we can rewrite the expression as:

256/41 - 31/14 - 11/21

To add or subtract fractions, we need to find a common denominator. In this case, the common denominator for 41, 14, and 21 is 574.

So, the expression becomes:

(256 14/41 14) - (31 41/14 41) - (11 21/21 21)
= (3584/574) - (1271/574) - (231/574)
= (3584 - 1271 - 231)/574
= 2082/574

Finally, we can simplify the fraction by dividing both the numerator and denominator by their greatest common factor, which is 2:

2082/574 = 1041/287

Therefore, 5 11/41 - 2 3/14 - 11/21 simplifies to 1041/287.