Answer:
(-7.5, 3.5)
Step-by-step explanation:




(4/9)/x = 12
(4/9) = 12x
Divide both sides by 12
(1/27) =x
The GCF of the three terms (9a, -18b and 21c) is 3
Rewrite each of the terms so 3 is a factor
9a = 3*3a
-18b = -3*6b
21c = 3*7c
So we can say...
9a - 18b + 21c = 3*3a - 3*6b + 3*7c
9a - 18b + 21c = 3(3a - 6b + 7c)
Answer: 3(3a - 6b + 7c)
If you distribute outer 3 to each of the inner terms and multiply, you'll get the original expression again.