Ineed and have the work with the ones that are harder

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

How many kilograms of a 5% salt solution and how many kilograms of a 15% salt solution must be mixed together to make 45kg of an 8% salt solution?

What are two numbers that add up to -9 and multiply to -10 best answer gets branliest and 100 extra points