Find the value of x for which line a is parallel to line b. (21)

X is 20 degrees. Since it says that lines a and b are parallel and angles four and five are right next to each other, it means that when you add the two of them together you’ll get 180. Since it’s replaced with variables with coefficients, add the coefficients to get 9 and divide 180/9 to get 20. 20 is the value for x which is your answer