From the secon equation, we can find x in terms of y by doing:
x = 2 + y
Pluggin this value of x in the first equation:
2(2 + y) - 2y = 14
4 = 14
We reached a false statement, which means that the given system of equations has no solutions. Another way to verify that would be by dividing the first equation by 2. Doing so, we would have equation 1: x - y = 7 and equation 2: x - y = 2, which is clearly impossible!