Question

x-y=2 3x-3y=1

Answer 1

Uh...\[3x - 3y = 1 \implies x - y =\dfrac{1}{3}\]But\[x - y = 2\]

Answer 2

x - y = 2 -->x = 2 + y
now sub 2 + y in for x in the other equation
3x - 3y = 1
3(2 + y) - 3y = 1
6 + 3y - 3y = 1
3y - 3y = 7
0 = 7
There is no solution for this problem

Answer 3

oops...6 + 3y - 3y = 1
3y - 3y = 1 - 6
0 = - 5
still no solution :)