I changed the Refresh rate from 60hz to 120hz and now my xbox has a black screen no matter...

Dufful googling vsync will clear things up for you.... The standard refresh rate is 60hz using a 60hz or a 120hz. Xb1 uses 60 hz and wther u use 120hz or a common 60hz tv it doesnt matter screen tearing in that instance is not the tvs fault.

xb1' images is failing to vsync before being projected

no samsung 4k tv has 140 hz, probably 120hz, but that game aint gonna get nowhere near 120fps on the x so will be struggling to hit 40fps therefore screen tear. try changing refresh rate on x to 60hz and try.

Bah nevermind, I found the problem on another gaming forum! The game's framerate is tied to my monitor's refresh rate! I lowered it from 120hz to 60hz and now the game runs fine at 60 fps!

when i turn on freesync it automaticlly drops the hz down to 60, now way to have freesync on and 120hz

If FreeSync "drops" to 60, this means that the game is only able to render in 60 fps. The publisher probably frame locked the game to run at 60Hz, and not more.

FreeSync doesn't make frame rates go higher. FreeSync means, that the monitor refreshes the screen at the same fps/Hz rate as the game is rendering a full screen image.

If a game runs at 60 or 30 or less frames per second, the monitor adjusts to that frame rate. And if the game has enough resources and is not frame limited to render frames faster than 60Hz, the monitor will also follow that refresh rate and refresh the
screen display at the same rate as the game is sending a screen image.

Not all games are frame unlocked, and therefore not all games run at 120Hz, and so if you turn on FreeSync, and the monitor "drops" to a certain fps/Hz refresh rate, it's because the game won't send frames faster than that.

From the support page:

• Your display must support 120Hz over HDMI. While some monitors support 120Hz over DisplayPort, they may not support it over HDMI.
• 120Hz is only available for 1080p and 1440p. If you change your resolution to 4K UHD or 720p, the refresh rate will be set to 60Hz by default.
• If your console is set for 4K UHD and you change your refresh rate to 120Hz, your resolution will be downgraded to the highest resolution available for your display.