
Patrick B. answered 09/22/20
Math and computer tutor/teacher
The result is NOT the identity matrix, so there are infinitely many solutions.
the equations that survive are
x2 +x4 = 4
x3 - 5*x4 = 5
So for free var x4, x2 = 4 - x4 and x3 = 5(x4+1)
we need the original equations to write x1 in terms of x4