104k views
4 votes
Find the determinant of the matrix.

| 6 9 1 |
| 9 9 2 |
| 2 8 10 ∣

D = -277
D = -278
D = -279
D = -276
D = -272

1 Answer

0 votes

Answer:

-276

Explanation:

We'll use the method of cofactors. Use the coefficient +6 for

9 2

8 10

This gives you one third of the solution: 6 {(9)·(10) - (8)(2) }, or 444.

Next, use the coefficient 9, taking care to change the sign to -9 as follows:

9 1

-9 | | = -9(90 - 8) = -9(82) = -738

8 10

Finally with +2 as y our coefficient, evaluate the cofactor

9 1

9 2

ending up with

+2(18-9) = +2(9) = 18

Finally add these three results together:

+444 - 738 + 18 = -276

This, the determinant, D, is -276 (the fourth answer choice)

User Jorge Novaes
by
5.5k points