How do you find the determinant of #((7, -1), (6, -2))#?

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Answer 1 · 2016-02-13T14:58:00

#-8#

The determinant of the #2xx2# matrix

#((a,b),(c,d))#

is equal to #color(red)(ad-bc)#.

Here, with the matrix

#((7,-1),(6,-2))#

we see that

#{(a=7),(b=-1),(c=6),(d=-2):}#

Thus, the determinant of the matrix is equal to

#ad-bc=(7)(-2)-(-1)(6)=-14+6=color(blue)(-8)#