The document you've provided contains several exercises, mainly focusing on complex numbers, vector spaces, differential equations, and calculus. Here's a summary of each problem:

1. Exercise 1 involves a complex polynomial $P(z)$, where you're asked to:

   • Calculate $P(2i)$ and $P(-2i)$.
   • Factorize the polynomial and solve $P(z) = 0$ in $\mathbb{C}$.
   • Plot points based on their complex affixes and describe a set $\Gamma$, then study a rotation transformation.

2. Exercise 2 explores vector spaces and linear transformations:

   • Prove certain vectors belong to subspaces $H$ and $G$.
   • Find the matrix of a linear transformation in different bases.
   • Analyze the characteristics of a given endomorphism $f$.

3. Exercise 3 starts with solving a second-order differential equation $y'' - 4y' + 4y = 0$, followed by studying a piecewise function for properties like continuity, limits, and asymptotes.

4. Exercise 4 deals with statistical data adjustment and regression, where you calculate means, covariance, and determine an unknown parameter $\alpha$ based on the linear relationship.

5. Bonus exercise introduces a probability distribution on a random variable $X$ over six outcomes, asking for the probability law, distribution function, and moments (expectation, variance, etc.).

If you'd like, I can walk through the solution for any of these exercises step by step. Let me know which problem you'd like to start with!

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Would you like details on:

1. The complex polynomial factorization and solving?
2. The matrix of the endomorphism in vector spaces?
3. The differential equation and function analysis?
4. The linear regression and covariance problem?
5. The probability distribution?

Tip: When solving a polynomial equation, start by checking for simple roots using substitution and factorization.