Cobb Douglas Utility

Suppose that a consumer of two products, x and y, has preferences that can be represented by a Cobb-Douglas utility function of the form:

U = x^0.25 * y^0.75

The consumer is subject to a budget constraint of the usual form:

M = Px*x + Py*y

The demand equations corresponding to this utility function can be shown to be:

x = 0.25*M/Px

y = 0.75*M/Py

Please answer the following questions:

1. Suppose that the prices of x and y are both 1 initially, the consumer has $100 of income, and the government decides to levy a tax on x that would raise its price to 2. What is the compensating variation for this policy?
2. What are the income and substitution effects for good x induced by the policy?