Can i get some help with question 1 and 2

An assembly consists of two mechanical components. suppose that the probabilities that the first and second components meet specifications are 0.87 and 0.84. assume that the components are independent. determine the probability mass function of the number of components in the assembly that meet specifications. x

Use composition to determine if (x) or h(x) is the inverse of f(x) for the limited domain x2-1.

Bring the fraction a/a-4 to a denominator of 16-a^2