Answer: 75
Explanation:
For the lines to be parallel, this means the given angles have to be congruent (because then the lines will be parallel by the converse of the corresponding angles theorem)
- 2x - 45 = x + 30 [congruent angles have equal measure]
- x - 45 = 30 [subtract x from both sides]
- x = 75 [add 45 to both sides]