Question 162528
Do you mean like this??
{{{(matrix(2,2,6,5,4,-2))(matrix(2,2,x[1],x[2],x[3],x[4]))=(matrix(2,2,18,49,-20,6))}}}
First find the inverse of your first matrix, which we'll call [A].
[A]={{{(matrix(2,2,6,5,4,-2))}}}
and the inverse of A called [A]inv. 
[A]inv={{{-(1/32)*(matrix(2,2,-2,-5,-4,6))}}}
and then matrix multiply both sides to solve for [X]. 
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The problem would then look like this,
[A][X]=[B]
[A]inv[A][X]=[A]inv[B]
[I][X]=[A]inv[B]
[X]=[A]inv[B]
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So we do the matrix multiplication,
[X]={{{-(1/32)*(matrix(2,2,-2,-5,-4,6))*(matrix(2,2,18,49,-20,6)))}}}
[X]={{{(matrix(2,2,-2,4,6,5))}}}