Finding An Initial Speed, Intro to Physics Question

[STEF2098]

A boy tosses a coin straight up to 2.8 m. Suppose the height when the coin leaves his hand is 1.2 m. What was the initial speed of the coin when it left his hand?

I'm just confused as to what equation to use. And I don't know whether to assume the acceleration is -9.8 m/s^2. Thanks.

 

[Matterwave]

You can do this either with forces, or with conservation of energy. The conservation of energy method is much simpler, but I'm not sure if you've learned it yet.