Solve for x the Solution set is?

Question

Matrix is 3  X 3

 

2  4   x

1 -3 -6   =-8

3  5   8

Answer 1

I assume that the left side of your equation is the DETERMINANT of the visible 3by3 matrix.

 

Evaluate the determinant by any method known to you, e.g. Sarrus' method (where you append columns 2 & 3 and do the 'down the diagonals' method...) or the more conventional expansion using a selected row (or column) and cofactors & minors.  Most of the arithmetic in this expansion will involve only integers, but in some places the x will appear; therefore you'll have a linear equation involving x, and the right side will be -8.  It's doable!