Question 30886
let us set the equations is y=mx+b form.....where m is the slope and b is the y-intercept
x -y =7
-y = -x + 7
y = x - 7
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3x + y =5
y = -3x + 5 

the slopes are different, so they are not parallel.... that means the lines are perpendicular; if you combine the equations, you get (3,-4)