3: independent
4: dependent
<span>Definition: The number of square units it takes to exactly fill a sector of a circle.
Do you want the exact equation? arc length is </span>Area= rl/2 and arc length is the same as sector area
Factor this by grouping. Group the first two terms together and then the second 2 terms together. The idea here is that, after grouping, what you can pull out in both groups is the same. Like this:

Now work on finding a common thing between the 2 groups:

See, what you have in common there now is the (x-9) that you can factor out:

And that is factored completely.
Answer:
Correct answer is 21. I believe someone said it was 25 earlier, they are wrong. 21 is correct. (D)
Step-by-step explanation: