The sum of two numbers is 39 the larger number is 11 more than the smaller number

Write the slope-intercept form of the line that passes through the point (1, 0) and is parallel to x - y = 7. t

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Ineed someone to me answer my question i have to have this done and knocked out