question_answer

If \[\left( \frac{a}{2},4 \right)\] is the mid-point of the line segment joining the points \[A(-6,5)\] and \[B(-2,3),\] then the value of a is: (CBSE 2011)

A) \[-8\]

B) \[3\]

C) \[-4\]

D) \[4\]

Correct Answer: A

Solution :

[a]

Since P is mid-point of line segment AB, then

\[\frac{-6+(-2)}{2}=\frac{a}{2},\,\,\,\frac{5+3}{2}=4\]

\[\Rightarrow \,\,\,\,\,\,\,\,\,\,\,\frac{-8}{2}=\frac{a}{2}\,\,\,\,\,\Rightarrow \,\,a=-8\]