Hi, I am in difficulty when I kept trying to do these questions.

Could you give me a help to solve these questions?

Thank you so much.

Q3 (2 points) Let the random variable X represent the lifetime of a set of car tires (measured in years) before they need to be replaced. The distribution of X can be modelled by the pdf 7 e otherwise (a) Find the expected lifetime of a set of car tires. (Hint: integration by parts. Be careful with setting up your improper integral here.) (b) Find the median lifetime of a set of car tires