Mark the correct alternative in each of the following:
If 
and 
points are collinear, then a is equal to
A (
, B (
) & C (
) are collinear,
Then 
Comparing the LHS & RHS of the above mentioned equation,
-80 = a – 40
a = 40 – 80
a = -40
a = -40
Option (B) is the answer.
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