How do you find the determinant of #((2, -2, 2), (1, 2, 4), (3, 0, 5))#?

1 Answer
Gió
May 16, 2016

I found #-6#

Explanation:

I would add the first line to the second to get:
#((2,-2,2),(3,0,6),(3,0,5))#
I would then cancel the first line and second row maintaining the intersection corresponding to #-2# and a minus sign corresponding to its position in the sequence:
#((+,-,+),(-,+,-),(+,-,+))#
getting:
#color(red)(-)(color(blue)(-2))((3,6),(3,5))#
or:
#2((3,6),(3,5))#
and a determinant of:
#2[(3*5)-(6*3)]=-6#

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