We can start to solve this system by simplifying the values. 2x + y = 5 already looks nice, so we can start to focus on 3y = 15 - 6x.
3y + 6x = 15 - 6x + 6x Get rid of -6x
(3y + 6x)/3 = 15/3 Simplify
2x + y = 5
Since we see that the equations are the same, the answer is the graph of the line created by this system (this is a place where it's very easy to get confused). To create the graph, we can first put the equation in y = mx + b format. This makes the equation become y = -2x + 5
The graph is here, and the answer is any point on this line: