Answer:
[tex]\displaystyle 6 = x[/tex]
Step-by-step explanation:
Since DF is a SEGMENT BISECTOR, you set 15x and 8x + 42 equal to each other:
8x + 42 = 15x
- 8x - 8x
___________
[tex]\displaystyle \frac{42}{7} = \frac{7x}{7} \\ \\ 6 = x[/tex]
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