` |(-2,3,-1),(5,-1,4),(4,-8,2)|` ` =-2|(-1,4),(-8,2)|` ` -5|(3,-1),(-8,2)|` ` +4|(3,-1),(-1,4)|`

`= -2[(-1)(2) − (-8)(4)] − 5[(3)(2) ` `{: − (-8)(-1)] ` `+ 4[(3)(4) ` `{: − (-1)(-1)]`

`= -2(30) − 5(-2) + 4(11)`

`= -60 + 10 + 44`

`= -6`

Here, we are expanding by the first column. We can do the expansion by using the first row and we will get the same result.

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