Determinant Evaluation

I have the following determinant.

Code:

---

|1 2 3 4|
|5 6 7 8|
|2 6 7 8|
|3 1 1 2|

---

So is my evaluation correct?

Code:

---

1 x  |6 7 8| - 2 x |5 7 8| + 3 x |5 6 8| - 4 x |5 6 7|
    |6 7 8|      |2 7 8|      |2 6 8|      |2 6 7|
    |1 1 2|      |3 1 2|      |3 1 2|      |3 1 1|

---

Yes.