A stick of butter is the same as 8 tablespoons, or 1/2 cup. A cookie recipe calls for 3/4 cup butter. How much butter is this?

Think about this... it's simple addition. We can't do your homework for you, but if you show some initiative we are willing to help.

If 8 tbsp. = 1/2 cup, then how many tbsp. = 3/4 cup? Simple proportion.

The problem here, the question does not ask explicitly to give the answer in what units. It could be in tablespoons or sticks...

In anyway, both of them involve simple proportions. Perhaps giving the answer in both units is what the question is asking.

Get a stick of butter and look at it. Most have the measurements on the wrapping paper.

Haven't done much cooking, huh? Even if the OP is even in elementary school, now is a good time to start.