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1965 IMO Problems/Problem 2

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Problem

Consider the system of equations a_{11}x_1 + a_{12}x_2 + a_{13}x_3 = 0 a_{21}x_1 + a_{22}x_2 + a_{23}x_3 = 0 a_{31}x_1 + a_{32}x_2 + a_{33}x_3 = 0 with unknowns x_1, x_2, x_3. The coefficients satisfy the conditions:

(a) a_{11}, a_{22}, a_{33} are positive numbers;

(b) the remaining coefficients are negative numbers;

(c) in each equation, the sum of the coefficients is positive.

Prove that the given system has only the solution x_1 = x_2 = x_3 = 0.

Solution

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