Answer :

Ematio
The first one has a negative. You shouldn't have a negative isolated variable,
-x = 5y -1, Multiply everything by -1,
x = -5y + 1,

For the second one, you isolate the x,
x + 2y = 13, subtract 2y from both sides,
x = 13 - 2y.
konrad509
[tex]x=5y-1\\ x+2y=13\\\\ 5y-1+2y=13\\ 7y=14\\ y=2\\\\ x=5\cdot2-1\\ x=9\\\\ \boxed{(x,y)=(9,2)}[/tex]