NO. They are two different search engines meaning they use different algorithms. So if you are optimizing for Google you should know the ranking factors.
Yahoo and google are not the same so it is not possible that yahoo can make you page rank high in google..
Hi. Google is the best way to increase the traffic of your site but Yahoo has its own policy and conditions. It uses its own algorithms. So answer is no.
O'key. Both have different methods, but they take into consideration amount of traffic totally. Not only those that entered website from an appropriate search engine. So, the more people enter the website from Google, the higher it's total rating should be (not only the one from google or yahoo)
Concentrate on quality content, then ranking, once you rank high in one, do the same for the other search engine.
I have heaard something about that, it was related to yahoo answers, getting a good back link from there can improve your SERP.