Fill in the blank so that the resulting expression can be factored as the product of the two linear equations
21mn - 21m + 19m + 6n - 14n + 8 + ___
Simplify as
21mn - 2m - 8n + 8
Add -19m
So we have
21mn - 21m - 8n + 8 =
21m ( n - 1) - 8 (n - 1) =
(21m - 8) ( n - 1)
+1348 
