Fill in the blank with a constant, so that the resulting expression can be factored as the product of two linear expressions:
2mn - 21m + 6n + 15m - 5n + ___
As follows:
Simplify as
2mn - 6m +n + ____
2m ( n - 3) + (n - 3) =
(2m + 1) ( n - 3) =
2mn - 6m + n - 3 =
2mn - 6m + n + (-3)
+1791 
