Q12 of 184 Page 10

If the distances of P(x, y) from points A(3, 6) and B(- 3, 4) are equal, prove that 3x + y = 5

Given points are A(3, 6) and B(- 3, 4). It is told that S(x, y) is equidistant from A and B.



So, we get SA = SB,


We know that distance between two points (x1, y1) and (x2, y2) is .


Now,


SA = SB


SA2 = SB2


(x - 3)2 + (y - 6)2 = (x - (- 3))2 + (y - 4)2


(x - 3)2 + (y - 6)2 = (x + 3)2 + (y - 4)2


x2 - 6x + 9 + y2 - 12y + 36 = x2 + 6x + 9 + y2 - 8y + 16


12x + 4y = 20


3x + y = 5


Thus proved.


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