In math, "of" almost always means "times".
So your question is: 3/7 times (the number) = 9
Multiply each side of that equation by 7 : 3 times (the number) = 63
Divide each side by 3 : <em> The number = 21</em>
Answer:
D. be congruent
Step-by-step explanation:
vertical angles are angles that are across from each other on intersecting lines and they are always congruent
Step-by-step explanation:

10 + 6n = 4 - 4n
I'm just guessing but I'm pretty sure that's it.