The half-life of Mathium is 23 days. A 15 g sample of the element is monitored over time. a) Write an equation that models the mass of Mathium remaining over time. Define variables clearly. b) Determine the number of days it would take for there to be 1.05 g of Mathium left.

Idon’t know what the answer is i wish i could

So the first thing we do is to multiply the top equation by 3. the reason i want to do this is i notice there will be a 6y on both equations and can possibly add/subtract them. so we get 6y = -3x + 27. adding that and the second equation we get 6x = 27-15 which is 12. divide by 6 and we get 2. ∴ x = 2. substituting 2 into the first equation we get 2y = -2 + 9 which is 7. divide by 2 and we get 7/2. ∴ y = 7/2, x = 2.