Hello from MrBillDoesMath!
Answer:
Choice A
Discussion:
As the lines are parallel, corresponding angles are equal. This means that
angle x (just to the left of the letter a) and its corresponding angle ( just above line b -- above the the "2x" value shown) are equal..
In other words,
x = 180 -2x
as there is 180 degrees in a straight line.
Add 2x to both sides of the equation:
x + 2x = 180 - 2x + 2x =>
3x = 180 =>
x = 60
Regards,
MrB
