Question 1049495
<pre><b>
I'll just do (c). 

{{{matrix(1,10,A,""="",(matrix(3,2,-4,0,1,-5,-3,2)),"","","","",B,""="",(matrix(3,2,1,2,-2,1,4,4)))}}}

          {{{ 6x - 4A - 3B}}}{{{""=""}}}{{{0}}}

Get the x-term on the left just like you would 
in any ordinary equation:

Add 4A and 3B to both sides:

          {{{6x}}}{{{""=""}}}{{{4A+3B}}}

Don't divide by 6 yet.  We'll do that at the end.

Substitute the matrices for A and B in that equation:

{{{matrix(1,7,6x,"",""="","",4(matrix(3,2,-4,0,1,-5,-3,2)),""+"",3(matrix(3,2,1,2,-2,1,4,4)))}}}

Distribute the 4 and the 3 into all 6 elements
(numbers) in each matrix:

{{{matrix(1,7,6x,"",""="","",(matrix(3,2,4*-4,4*0,4*1,4*-5,4*-3,4*2)),""+"",(matrix(3,2,3*1,3*2,3*-2,3*1,3*4,3*4)))}}}

Simplify:

{{{matrix(1,7,6x,"",""="","",(matrix(3,2,-16,0,4,-20,-12,8)),""+"",(matrix(3,2,3,6,-6,3,12,12)))}}}

Add corresponding elements in the two matrices:

{{{matrix(1,5,6x,"",""="","",(matrix(3,2,-16+3,0+6,4+(-6),-20+3,-12+12,8+12)))}}}

Simplify:

{{{matrix(1,5,6x,"",""="","",(matrix(3,2,-13,6,-2,-17,0,20)))}}}

Divide both sides (every element in the matrix) by 6:

{{{matrix(1,5,(6x)/6,"",""="","",(matrix(3,2,-13/6,6/6,-2/6,-17/6,0/6,20/6)))}}}

Simplify

{{{matrix(1,5,x,"",""="","",(matrix(3,2,-13/6,1,-1/3,-17/6,0,10/3)))}}}

It's not all that different from solving ordinary equations.

Edwin</pre></b>