Answer:
○ b. 
Step-by-step explanation:
Since <em>DF</em><em> </em>is a segment bisector, set both expressions equal to each other:
3n - 4 = n + 8
-3n - 3n
__________
−4 = −2n + 8
-8 - 8
_________
−12 = −2n
__ ___
−2 −2
[Plug this back into both expressions above to get the value of 14]; 
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Answer: The largest angle is 7x
Step-by-step explanation:
Their sum is 180, so
3x + 5x + 7x = 180
5x = 180 --> x = 12
The largest angle is 7x, which is 7(12) = 84