About 80% of the precipitation that enters Crater Lake falls directly on the surface of the lake. Write this percent as a decimal. I really need help on this one. ·ω·

(9x-5) - (x+12) what’s the answer and also explain how to do it i need it for a test tomorrow

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?

The fence around a quadrilateral-shaped pasture is 3a^2+15a+9 long. three sides of the fence have the following lengths: 5a, 10a-2, a^2-7. what is the length of the fourth side of the fence?