To simplify this expression, we first need to simplify the terms inside the parentheses:

-2/7 - 1/4 = (-8/28) - (7/28) = -15/28

Now we can substitute this back into the original expression:

-25/14 - (-15/28) - 1/9

To subtract a negative number, we can change it to addition:

-25/14 + 15/28 - 1/9

Now we need to find a common denominator for 14, 28, and 9, which is 252:

-25/14 * 18/18 = -450/252
15/28 * 9/9 = 135/252
1/9 * 28/28 = 28/252

Now we can substitute these back into the expression:

-450/252 + 135/252 - 28/252 = -343/252

Therefore, -25/14 - (-2/7 - 1/4) - 1/9 simplifies to -343/252.