Question 434161
The area is equal to {{{(1/2)abs(det(A))}}}, where {{{det(A)}}} is the determinant of the 3x3 matrix formed by using the vertices with a set of 1's. The matrix we are evaluating is equal to

     0   5   1
     7   1   1
    -3  -2   1


I'll leave the arithmetic to you.