In this thesis the generalized eigenvalue problem is described. The generalized eigenvalues are computed by QZ algorithm and its corresponding generalized eigenvectors are computed by method which is called inverse iteration. The QZ algorithm is based on the QR algorithm. This QR algorithm solves numerical eigenvalue problem - calculates eigenvalues. The corresponding eigenvectors are computed by inverse iteration too. The QR iteration is based on QR-decomposition of the matrix A so that A = QR where Q is the orthogonal matrix and R is the upper triangular matrix. The matrix A can be decomposed in several ways. For example we can use the Householder matrix of reflection or Givens matrix of plane rotation or Gram-Schmidt algorithm for decomposition of the matrix A.