Question

Cosider a, b, c : real numbers. $X=\frac{a+b}{a-b},Y=\frac{b+c}{b-c},Z=\frac{c+a}{c-a}$
What is tha value of XY + YZ + XZ ?

• A. 1
• B. 2
• C. 3
• D. none of these

Answer 1

The correct option is D none of these

Option (e)

Assume a=1, b=2, c=3

X=-3 Y=-5 Z=2

XY+YZ+XZ=15-10-6=-1

Assume a=2, b=3 and c=4

X=-5 Y=-7 Z=3

XY+YZ+XZ= 35-21-15= -1

Hence answer =e