AB is a straight line solve for x please help this quiz is so hard

Answer:
x = 29
Step-by-step explanation:
Since AB is a perfectly straight line, that means its angle is exactly 180°. Given that, we can tell that the three angles all add up to 180°. If we set the equation to equal 180 by adding all the given angles up, we will find the answer.
64 + x + 3x = 180
Combine like terms.
64 + 4x = 180
Subtract 64 from 180 to get 4x by itself.
180 - 64 = 116
4x = 116
Now get "x" completely alone by dividing both sides of the equal sign by 4.
4x/4 = x
116/4 = 29
x = 29