Answer:
x = 45 degree as it is an alternate angle we use 135 degree to prove supplementary angles across the straight line add up to 180 degree.
Therefore we prove 180-135 = 45 degree and say all angles on straight line add up to 180 degree, and recognize x is an alternate angle as the arrow straight lines are parallel and create precise alternate lines from which we can prove multiple supplementary and alternate angles.
Supplementary can be either angle will always be supplementary from either 45 degree angle matched with any 135 degree as they don't have to be together to be supplementary they only have to equal 180 degree to be a supplementary angle.
Explanation: