Answer:
B and D
Explanation:
is it really that difficult ?
what was the problem ? please let me know, if you need further explanations.
A.
a length can never be negative. a length is either 0 or something is this or that much apart from something else. the direction does not matter. a distance is a distance and therefore positive. so, this is wrong.
B.
is clearly right. the distance from B (1) to C (6) is 6-1 = 5.
and just in case we would have calculated 1-6, the absolute value (always positive) is used. as again, direction does not matter when discussing distance. -5 or +5, the distance is always (+)5.
C.
AB + AC is counting the distance of AB twice. this is actually (just look at the graphic) AB + AB + BC. so, no, this is not equal to BC but much bigger. so, this is wrong.
D.
but yes, this is correct. again, just look at the graphic : AB + BC = AC
the 2 segments of the AC line combined are the AC line.