Question 1116288
How, depends what you know.


{{{system(x+5y-z=-17,x+y-z=-1,2x+5y-3z=-10)}}}


R2-R1 for new R2;
R3-2R1 for new R3;


{{{system(-4y=16,-5y-z=-8)}}}-------two linear equations, two unknown variables


{{{system(y=-4,z+5y=8)}}}


{{{system(y=-4,z=28)}}}--------two of the variables solved - and you can finish the remaining variable however you want.




(not the only way to solve)