Can someone pls help

Given: lines a and b are parallel and line c is a transversal. prove: 2 is supplementary to 8 what is the missing reason in the proof? statement reason 1. a || b, is a transv 1. given 2. ∠6 ≅ ∠2 2. ? 3. m∠6 = m∠2 3. def. of congruent 4. ∠6 is supp. to ∠8 4. def. of linear pair 5. ∠2 is supp. to ∠8 5. congruent supplements theorem corresponding angles theorem alternate interior angles theorem vertical angles theorem alternate exterior angles theorem

4. bob solved the inequality problem below incorrectly. explain his error and redo the problem showing the correct answer. −2x + 5 < 17 −2x + 5-5 < 17-5 -2x/-2 < 12/-2 x < -6

How do i i solve this equation? -18 = x/3 + 3