Google will attempt to find out by itself whether or not these query string parameters are showing new content, or are just used for tracking and do nothing to the page.
However, you can specify how Google should handle parameters via webmastertools. Go to Crawl --> URL Parameters, and then you will see the parameters that google recognized (you can also add them manually). Then, you can choose between letting Google decide what to do with it, or to specify manually whether it "Doesn't affect page content" or Changes, Reorders, or narrows.
See here an example:
Since it's a search form, and it shows content that appears on other URLs of the site, I'd just leave it for Google to handle to see what happens. Most of the time I leave it on default (let googlebot decite) and so far I did not encounter major problems, SEO-wise.
If you choose "Yes", read Google's documentation first since there are different ways to handle multiple parameters, such as in your case, depending on the behavior of your search form and on what you want to reach: