Thank you for the opportunity to help you with your question!

In dealing with homework problem, you have to go by the following steps:

1. Under the exercise taxes and welfare computing,

First, compute the indirect utility function and express the welfare as the utility in the tax rate.

Secondly, show the imposition of the reduction of tax in the welfare terms.

Consider the welfare loss according to the surplus which is calculated on the assumption that the disposable income remain at its in initial level.

Don't forget the revenues which are also done in assumption that disposable income remain at its initial level.

Lastly suggest a way to compare the methods of welfare effect evaluation of an exercise tax.

2. In public goods and misrepresentation preferences, consider two individuals who have both invested to produce a public good according to the production transformation relation.

With those points, your homework problem will be positively solved.

Please let me know if you need any clarification. I'm always happy to answer your questions.