Question 41946
Consider the second equation {{{-2x-10y=-20}}}.
This can be simplified into {{{2x+10y=20}}} or {{{x+5y=10}}}.
Thus the second equation is identical with the first one.
So the system is dependent.


So, ultimately, we are left with only one equation {{{x+5y=10}}} but 2 unknowns.
To determine 2 unknowns we need two different equations; otherwise from one equation we cannot find a unique solution.