What is the equation of this circle?

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?

Which equation represents a direct linear variationa. y=x2b. y=2/5xc. y=1/xd. y=x+3

Will give brainliest for correct answer 8. use the distance time graph to answer these questions: a. what does the graph tell us about the velocity of the car? b. what is the average velocity of the car? (show work) c. is the velocity reflected in the graph positive or negative?d. is there any point on the graph where the car is not moving? how do we know?