Answer:
The lines are parallel.
Explanation:
The first line is
![x-y=1](https://img.qammunity.org/2020/formulas/mathematics/middle-school/6y6exdtoaof5nmlx289zid7qeqz3x3bxqj.png)
In slope-intercept form, this line has equation:
![y=x-1](https://img.qammunity.org/2020/formulas/mathematics/middle-school/491mp1q5sy2enfm9jjqpuljbot145tqepz.png)
The second line is
![y-x=1](https://img.qammunity.org/2020/formulas/mathematics/middle-school/k0ix8zls2all1z4detutprdb9kongt8fod.png)
In slope-intercept form, the line has equation:
![y=x+1](https://img.qammunity.org/2020/formulas/mathematics/middle-school/rwcyp2zhoac783ugzjl02t5nu74wceg9ee.png)
The slopes of the two lines are the same (m=1)
however, the y-intercepts of these lines are different (-1) and (+1) respectively.
The first choice is correct.
The two lines are parallel and hence will never intersect.