Let's simplify the expression step by step:

First, distribute the coefficients:

25(x) + 25(2) - 4(y) - 4(-3) - 25(x) + 4y - 61

This simplifies to:

25x + 50 - 4y + 12 - 25x + 4y - 61

Combine like terms:

(25x - 25x) + (4y - 4y) + (50 + 12 - 61)

This simplifies to:

0 + 0 + 1

Therefore, the simplified expression is:

1