Answer:
a= 60 degrees
b = 50 degrees
Explanation:
Angle a is 60 degrees because the angle of a straight line is always 180 so if you do 180-120 you get 60 (the remaining angle of the straight line)
The three angles of a triangle also always add up to 180.
so if you add 70 + 60 you only get 130 and 180 - 130 equals 50