Answer:
length/distance = 10 units
Explanation:
Use the distance formula for both points / length / magnitude, d = √((x2-x1)^2+(y2-y1)^2).
Given endpoints (-3,8) [(x1,y1)], and (7,8) [(x2,y2)], plug in the corresponding y, and x values of both coordinates, and simplify.
√((8-8)^2+(7-(-3))^2) = √(0^2+10^2) = √100 = 10
*This may be in units if the unit used is unspecified.*
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Also since the y values of both coordinates are the same, you can just subtract the x values in the coordinates, and take the absolute value since distance/length cannot be negative.