Solve for the matrix and please show all work. 

Put in all the  coefficients and make the  a 





Now erase all the letters and you have



The idea is to get three 's in the lower left corner:
Multiply the top row through by -12



Add the top row to the middle row:



Restore the top row



Multiply the bottom row by -2


Add the middle row to the bottom row:



Now we've gotten three 's in the bottom left.
So we make the matrix back into 3 equations:





Drop the 0 terms and make the 1's invisible:





Solve from the bottom to top.
Solve the bottom equation for 





Plug that into the second equation:








Plug that and  into the first
equation:






So

(,,) = (,,)

Edwin