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Mathematics · Coordinate Geometry · NCERT Examples

Example 4

A complete, independently verified solution for NCERT Example 4.

Mathematics · Chapter 7 · NCERT Examples

Verified NCERT questions and solutionsSolutions are checked independently and follow the supplied NCERT chapter edition.

NCERT Example

Example 4

Find a relation between x and y such that P(x, y) is equidistant from A(7, 1) and B(3, 5).

Coordinate axes showing A(7, 1), B(3, 5), and their perpendicular bisector x minus y equals 2.
Figure 7-7 from the supplied NCERT chapter.

Solution

Board-exam working:

Since P is equidistant from A and B:

AP=BPAP=BP

Squaring both sides:

AP2=BP2AP^2=BP^2
(x7)2+(y1)2=(x3)2+(y5)2(x-7)^2+(y-1)^2=(x-3)^2+(y-5)^2

Expanding both sides:

x214x+49+y22y+1=x26x+9+y210y+25x^2-14x+49+y^2-2y+1=x^2-6x+9+y^2-10y+25

Cancelling equal terms and simplifying:

14x2y+50=6x10y+34-14x-2y+50=-6x-10y+34
8y8x+16=08y-8x+16=0
xy=2x-y=2

Final answer

The required relation is x - y = 2.