without even graphing the equation you can tell that both functions are the same function. if you multiply the function x+2y=4 by 2, it will be 2x+4y=8, and therefore the solution is all real numbers
2(x+2y)=(4)2......2x+4y=8
if a graph is still necessary iv'e added one with this answer. As you can see in the graph, the first function is represented by a dotted blue line and the second graph is represented by a dotted pink line, and the are both the same function. if you have any questions id be glad to help :)