Answer:
54°, 126°
Step-by-step explanation:
Add up the terms and divide by the coefficient of x. Then use that value of x to find the value of each of the terms.
9x + 21x = 180
30x = 180 . . . . . collect terms
x = 6 . . . . . . . . . .divide by 30
Then the terms are ...
9x = 9·6 = 54
21x = 21·6 = 126
We assume this means your angles are 54° and 126°.
