Element X is a radioactive isotope such that every 81 years, its mass decreases by half. Given that the initial mass of a sample of Element X is 1800 grams, how much of the element would remain after 28 years, to the nearest whole number?

Ametalworker has a metal alloy that is 30? % copper and another alloy that is 55? % copper. how many kilograms of each alloy should the metalworker combine to create 90 kg of a 50? % copper? alloy?

Iam stuck on one problem. my mind is in absoloute vacation mode. i literallty just need to finish this to be done will give brainliest and all my points if i have to! 1- point free throw and 2- point feild goal. he made 35 shots, and scored 62 points how many of each shot did he make in 1 minute? (i already did the math. he made 8 1-point free throws and 27 2-point feild goals.) 1. write two equations for the problem. (i had a major brain fart.)

Solve for x, y, and z. show all steps.