Answer:
Explanation:
Comment
This is not an ordinary question. It is a little tricky. The slanted line making one arm of the angle 2x has three angles making it up. One is unmarked. Call it y.
Equations
2x + 90 + y = 180
3x + y = 120 which we have to prove.
Solution
The lower right angle of the parallelogram and the 60 degree angle are supplementary. Label that angle as z.
z + 60 = 180 Subtract 60 from both sides
z + 60-60 = 180 - 60 Combine
z = 120
z = 3x + y Opposite angles of a parallogram are equal.
Hence 120 = 3x+y
Now to deal with 2x
2x + 90 + y = 180 All three angles make up the slanted line.
Subtract 90 from both sides
2x + 90-90 +y = 180-90 Combine
2x + y = 90
Now you have 2 equations for 2 unknowns. Lets write them together.
3x + y = 120
2x + y = 90 Subtract.
x = 30
Answer: x = 30