Verified answer

l 1 -4 1 l

l -3 5 1 l

l 4x 3 1 l=

[1*5*1+-4*1*4x+1(-3)*3]-[(-4(-3)*1+1*1*3+1*5*4x]=0

5-16x-9-(12+3+20x)=0

-16x-4-15-20x=0

-36x-19=0

-36x=19

36x=-19

x=-19/36