I'm going to need some assistance with this one..

Use implicit differentiation with respect to t on your starting equation, then plug in the given values. You weren't given a value for z, so your solution for dz/dt will still have a z in it.
 
Use implicit differentiation with respect to t on your starting equation, then plug in the given values. You weren't given a value for z, so your solution for dz/dt will still have a z in it.

Did I do this right?
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