Hi Michela,

Two issues to consider: some systems require quickmath.com (using the 'Advanced' tab):

https://quickmath.com/webMathematica3/quickmath/equations/solve/advanced.jsp#c=solve_advancedsolveequations&v1=2x-3%3D%285y%2B7z%29%2F2%0A%28x%2By%2Bz%29%2F%28x-2%29%3D6%0Ax%2B2y%2Bz%3D-8&v2=x%0Ay%0Az

Alternatively, apply some simply reordering so that the system of equations is more presentable:

4x-5y-7z=6

-5x+y+z=-12

x+2y+z=-8

click here to solve the system

The doyourmath.com solution as shown without solution steps [for brevity]:

The unaltered system, as solved through quickmath.com [no solution steps are possible since quickmath.com uses non-human heuristics]: