SOLUTION:

Question 1123009:
Answer by t0hierry(194) (Show Source): You can put this solution on YOUR website!
For the following system of linear equations, write the associated matrix equation (in the form Ax=b) and solve the matrix equation
2x1-3x2-7x3=-47
-4x1+6x2+8x3=64
add (2) times the first equation to the second equation:
4x1-6x2-14x3=-94
-4x1+6x2+ 8x3 =64
-6x3 = -30
x3 = 5
2x1 - 3x2 = -47 + 35 = -12.