Would it be more convenient to use substitution, elimination by adding or elimination by subtracting for the following two systems of equations? 1: 3x-2y=0 , 4x+2y=14 2: 6x-2y=18 , 6x+7y=12

As a general rule: if you find two opposite coefficients for the same variable, it is convenient to add. If you find two equal coefficients for the same variable, it is convenient to subtract.

In the first system, the coefficients of are -2 and +2. If you add those you get 0, and thus you eliminate the variable.

In the second system, the coefficient of is 6 in both equation. If you subtract those you get 0, and thus you eliminate the variable.