The document solves a system of 3 equations with variables x, y, and z. It finds the determinants of the coefficients matrix and the matrices from each equation (Δ1, Δ2, Δ3) and the overall determinant (Δ). It uses Cramer's rule to calculate the values of x, y, and z by taking the ratio of the determinants from each equation to the overall determinant, resulting in x=-2, y=5, z=7.