Question

Calcule os determinantes, aplicando a regra de Sarrus:

a)
|1 -3 4|
|0 2 5|
|1 3 -1|

b)
|2 x x|
|1 2 1|
|3 1 2|

c)
|-3 4 6|
|1 2 3|
|-7 -4 0 |

OBRIGADA <3

Answer 1

A-
|1 -3 4| 1 -3
|0  2 5| 0  2
|1 3 -1| 1  3
-8 -15 +0 -2 -15 +0 = -40

B-
|2 x x| 2 x
|1 2 1| 1 2
|3 1 2| 3 1
-6x -2 -2x +8 +3x + 1x = 0
-8x -2 +8 + 4x = 0
-4x +6 = 0
-4x = -6
x = -6/-4 = 1,5

C-
|-3  4 6| -3  4
| 1  2 3|  1  2
|-7 -4 0| -7 -4
+84 -36 +0 +0 -84 -24 = -60