Starting off, we can multiply the third equation by 2 and add it to the third to get rid of both the x and y variables. Next, we get z=1. Plugging that into 3y-5z=-23, we get 3y-5=-23. Adding 5 to both sides, we get 3y=-18. After that, we can divide both sides by 3 to get y=-6. Plugging that into -2x-y-z=-3, we get -2x+6-1=-3=-2x+5. Subtracting 5x from both sides, we get -2x=-8. After that, we can divide both sides by -2 to get x=4.