find the area of a triangle fgh f(1,4) g(-2,-3) h(3,-2) using matricies

Answer 1

Hard to show matrices in here, since columns don't line up nicely.
I would stack them up this way

1 4
-2 -3
3 -2
1 4

area = (1/2)[ downproducts - upproducts]
= (1/2) [ -3 + 4 + 12 - (-8 - 9 - 2) ]
= ....