x+y=6 subtract x from both sides
x=6-y, now use this value of x in the second equation:
2(6-y)+y=4 perform indicated multiplication on left side
12-2y+y=4 combine like terms on left side
12-y=4 subtract 12 from both sides
-y=-8 divide both sides by -1
y=8, now use this y in either original equation to solve for x, I'll use x+y=6
x+8=6 subtract 8 from both sides
x=-2
So the solution to the system of equations is the point (-2, 8)
