Solve the system using the inverse of the coefficient matrix of the equivalent matrix equation
The answer is 2,-1,4
Apparently you mean that . This is, of course, wrong...and I write "of course" because if you multiply this by you do not get the
identity matrix, so it shouldn't be a surprise that your answer doesn't match the actual one.
You have the first column correct, but all the other entries are wrong, so...do it again, this time more carefully!