Obtain an equivalent system by performing the stated elementary operation on the system. Replace the first equation by the sum of itself and 2 times the third equation.

-7x - 15y + 15z = 35

4x + 10y + 13z = -20

2x - 5y - 9z = 4

-7x - 15y + 15z = 35 ( )x - ( )y + ( )z = ( )

4x + 10y + 13z = -20 ( )x + ( )y + ( )z = ( )

2x - 5y - 9z = 4 ( )x + ( )y - ( )z = ( )

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