expressions equal to 12n - 8, dont necessarily need help but it would be cool if I received some answers

Gabriel paints flower pots to sell at a craft fair. she paints 2/5 of a flower pot teal, 1/4 of it yellow, and the rest of it white. what fraction of the pot is painted either teal or yellow?

Which of the fallowing best completes the sequence 5,10,15, a) 30 b) 22 c)25 d)35

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?