i need help on this but when you answer it can you actually explain how you got the answer because i dont understand

Apatient is given 50 mg dose of medicine the medicines effectiveness decreases every hour at a constant rate of 40% what is the exponential decay function that models this scenario how much medicine will be left in the patients system after 2 hours

Which function has an inverse function? a.f(x)= |x+3|/5 b. f(x)= x^5-3 c. f(x)= x^4/7+27 d. f(x)= 1/x²

Write 5(6x+4)-2(5x-2) in the form a(bx+c) where a,b and c integers and a> 1