Question 1138047


{{{matrix(3,3,2,x,1,-3,1,0,2,1,4)}}}={{{39}}}

The determinant is:

if you have
{{{matrix(3,3,a,b,c,d,e,f,g,h,i)}}}, then

{{{determinant= a(ei - fh) - b(di - fg) + c(dh - eg)=39}}}

in your case {{{a=2}}}, {{{b=x}}},{{{c=1}}},{{{d= -3}}},{{{e=1}}},{{{f=0}}},{{{g=2}}},{{{h=1}}},{{{i=4}}}

so, you have

{{{2(1*4 - 0*1) - x(-3*4 - 0*2) + 1(-3*1 - 1*2)=39}}}
{{{2(4 ) - x(-12 ) + 1(-5)=39}}}

{{{8  +12x -5=39}}}

{{{12x+3=39}}}

{{{12x=39-3}}}

{{{12x=36}}}

{{{x=3}}}