Discrete Math Question. I'm not sure what I did wrong for this question. ?
Suppose that a and b are integers where a ≡ 4 (mod7) and b ≡ 6 (mod7). Find the integer c with 0 ≤ c ≤ 6 such that c ≡ 2a + 4b (mod7).
I got 4 as my answer but the correct answer is 11. I'm not sure how you get that. Can someone please explain this?