1400x900

I know that someone already asked how to calculate the resolution of multiple monitors, but the question was about monitors with the same res.. so if I have a monitor which is 1440x900 and a monitor which is 1920x1080, what would be the resolution for let's say wallpapers that I would want to...

When I click on the lower left windows icon in windows 10 and click power and then shut off my monitor turns off but my tower stays on. Anyone know how to fix this? Thanks.