If you would like to know the value of x in the solution to the system of equations, you can find this using the following steps:
6x + 3y = 13
3x - y = 4 ... y = 3x - 4
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6x + 3y = 13
6x + 3 * (3x - 4) = 13
6x + 9x - 12 = 13
15x = 13 + 12
15x = 25
x = 25/15
x = 5/3
The correct result would be 5/3.