Question 37049
x+2y=5
3x-15=-6y

Solve the 1st for "x", as follows:
x=5-2y
Substitute that into #2 to get;
3(5-2y)-15=-6y
15-6y-15=-6y
0=0
This says the two equations are really the 
same equation.
So, what is the solution?
It is the infinite set of points that constitute the line.
Cheers,
Stan H.