Answer:
x = 20
Step-by-step explanation:
all of these together will come out to equal 180 degrees. Because it is a straight line. every straight lines is 180 degrees.
x + 3x + 100 = 180
simplify, 4x + 100 = 180
subtract 100 from both sides, 4x = 80
divide both sides by 4, x = 20
