a/19 has a remainder of 4. b/19 has a remainder of 2. c/19 has a remainder of 18.
2a/19 then must have a remainder of 8. (4 + 4 = 8)
The remainder of \(2a + b - c\) when divided by 19 is just \(8 + 2 - 18 = -8\). We can get the real remainder by adding -8 to 19, which equals 11. the remainder is \(\boxed{11}\).
Hope this helps,
- PM
+777 
Wow!