Question 69216
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(x 3)=2(x 2) solve for x
(4 x)= (1 3)
on each side of the equals sign is one matrix 
not to separate matices.

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

On the right distribute the {{{2}}}· into the whole matrix:

{{{(matrix(2,2,x,3,4,x))}}}={{{(matrix(2,2,2*x,2*2,2*1,2*3))}}}

{{{(matrix(2,2,x,3,4,x))}}}={{{(matrix(2, 2, 2x, 4, 2, 6))}}}

This has no solution because in order for two matrices to be 
equal, all corresponding elements must be equal.  But the upper
right element of the matrix on the left side is 3 and the upper
right element of the matrix on the right side is 4. Also the 
lower left element of the matrix on the left side is 4 and the 
lower left element of the matrix on the right side is 2.  They
would have to be the same if the matrices were equal. 

Did you perhaps mean them to be determinants, and not matrices,
like this?:

{{{ abs(matrix(2,2,x,3,4,x) ) }}}={{{ 2* abs(matrix(2,2,x,2,1,3))  }}}

If so then there is a solution.

The evaluation of a 2x2 determinant {{{abs(matrix(2,2,a,b,c,d))}}}
is {{{ad-bc}}}, so the determinant equation above becomes

{{{ x*x - 3*4 = 2(x*3-2*1) }}}

{{{x^2 - 12 = 2(3x-2)}}}

{{{x^2 - 12 = 6x - 4}}}

{{{x^2 - 6x - 8=0}}}

Solve that by the quadratic formula and get
         __
x = 3 ± <font face = "symbol">Ö</font>17

Edwin</pre>