Angles on a straight line add to 180 degrees. This means that the missing angle in the triangle is 180 - 9x + 9.
Next, angles in a triangle add up to 180 degrees. This means that:
45 + 5x + 180 - 9x + 9 = 180
We can simplify this down:
234 - 4x = 180
Now subtract 234 from both sides:
-4x = -54
Finally divide both sides by -4:
x = 13.5 degrees
Hope this helps!
