PLEASE HELP!

I suppose it is [3 5]
                        2 4

Er History I'm not sure...

I'm assuming you want the determinant of this matrix, which is \((-3)(4) + (-2)(5) = -22\). 

l c l  =   (-3)(4) - (5)(-2)  =    -12 - (- 10 )  =  -12 + 10 =   -2

Oh... I thought he meant the absolute value.