Sorry ask that question so wrong. true or false every whole number is a factor of 1? ?

1-for what value of x is line a parallel to line b 2-for what value of x is line a parallel to line b

Which of the following correctly justifies statement four of the two column proof? a. corresponding angles theorem b. transitive property of equality c. vertical angle theorem d. substitution property of equality

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