Element X is a radioactive isotope such that every 28 years, its mass
decreases by half. Given that the initial mass of a sample of Element X is 50
grams, how much of the element would remain after 11 years, to the nearest
whole number?

These question are hard can you me with answers

50 ! pls ! 12.  building codes regulate the steepness of stairs. homes must have steps that are at least 13 inches wide for each 8 inches that they rise.

a. discuss how to find the slope of the stairs.
b. describe how changing the width or height affects the steepness of the stairs.

Which one ? is the answer and how to find this answer