The coefficients of x are already opposites, so you can simply add the two equations to eliminate x.
... (-7x +3y) + (7x -2y) = (14) + (-14)
... y = 0 . . . . . . . simplify
... -7x + 3·0 = 14 . . . . substitute the value of x into the first equation
.. x = 14/(-7) = -2
The solution is (x, y) = (-2, 0).