Help me please I don't know what to do

Element x decays radioactively with a half life of 8 minutes. if there are 450 grams of element x, how long, to the nearest tenth of a minute, would it take the element to decay to 37 grams?

Find the slope of the line that contains the following points. r(-2, 4), s(6, -2)

What is the scale factor of two similar pyramids with volumes of 64 cubic feet and 8 cubic feet