1. Find three numbers for which the following is true: the sum of the first two is equal to the third, twice the third number is three more than the first, and twice the sum of the first two numbers is five more than the third.
1. If we write the numbers $a, b$, and $c$ in their appropriate mutual relationships: $a+b=c, a+3=2c$, and $c+5=2(a+b)$. We solve the system of three linear equations with three unknowns. We get the solution $a=7, b=-2$, and $c=5$.

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Correct procedure for solving the system of equations.......................................................................................................

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NOTE: For writing down two equations of the system, the contestant gets 1 point, for one equation no points. For writing down two solutions, the contestant gets 1 point, for one solution no points.