Answers:
The length of XY is 4
The length of ZW is 6
Because we don't get the same length (for XY and ZW), this means that the segments are not congruent.
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To find the length of segment XY, you can count the number of spaces between -7 and -3 to get 4 units. Or you can subtract and use the absolute value notation to ensure the result is positive
|-7-(-3)| = |-7+3| = |-4| = 4
Do the same for segment ZW.
|2-8| = |-6| = 6