For simultaneous multiple image adjustements, you have to be in one of two modes:
1) Library Grid View with multiple images selected in the Grid, of course, you can only use the Quick Develop adjustments.
2) In Develop Module with multiple images selected in the filmstrip, enable AutoSync mode, and any changes made to the 'most selected' photo will be echoed in the remaining selected images. To enable AutoSync, make sure multiple images are selected in the filmstrip and hold down ctrl-cmd, the Sync... button lower right, will turn to AutoSync, click it. Don't forget to turn it off when done!
Edit: oops, simulposting with VB, again.