Answer is 105 degrees.
Step-by-step explanation:
Given two parallel lines AB and CD and a transversal cutting the two lines.
We know that when a transversal cuts two parallel line,
i) corresponding angles would be equal
ii) Interior angles total to 180
iii) alternate angles are equal.
In the picture given we have corresponding angles as
(2,6) . Hence angle 2 = angle 6.
Angle 6 = 75 (given)
Hence angle 2 =75.
Angles 1 and 2 are supplementary because they form a linear pair.
Hence angle 1 = 180-75
Angle 1 =105