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1)

If A=[5,3], B=[3,-2] and a point P is such that the area of the triangle PAB is 9, then the locus of P  represents.


A) a circle

B) a pair of coincident lines

C) a pair of parallel lines

D) a pair of perpendicular lines

Answer:

Option C

Explanation:

Let P(x,y), A=(5,3),B=(3,-2)

Area of PAB= 12[xy1531321]

              9=12|x(3+2)y(53)+(109)|

     18=|5x2y19|

   5x2y16=|18|

     5x2y19=±18

   5x2y=19±18

     5x2y=1 or 5x2y=37

Which represents a pair of parallel lines