Find what the following equations become when the origin is shifted to the point (1, 1)?
Find what the following equations become when the origin is shifted to the point (1, 1)?

(i) x2 + xy – 3x – y + 2 = 0
(ii) x2 – y2 – 2x + 2y = 0

Solution:

(i) x2 + xy – 3x – y + 2 = 0

We will first substitute the value of x by x + 1 and y by y + 1. Then, te above-given ewuation becomes:

$ {{\left( x\text{ }+\text{ }1 \right)}^{2}}~+\text{ }\left( x\text{ }+\text{ }1 \right)\text{ }\left( y\text{ }+\text{ }1 \right)-3\left( x\text{ }+\text{ }1 \right)-\left( y\text{ }+\text{ }1 \right)\text{ }+\text{ }2\text{ }=\text{ }0 $

$ {{x}^{2}}~+\text{ }1\text{ }+\text{ }2x\text{ }+\text{ }xy\text{ }+\text{ }x\text{ }+\text{ }y\text{ }+\text{ }1-3x-3-y-1\text{ }+\text{ }2\text{ }=\text{ }0 $

Simplifying further we get,

x2 + xy = 0

Therefore, the transformed equation is x2 + xy = 0.

(ii) x2 – y2 – 2x + 2y = 0

We will first replace the value of x by x + 1 and y by y + 1

Then,

$ {{\left( x\text{ }+\text{ }1 \right)}^{2}}-{{\left( y\text{ }+\text{ }1 \right)}^{2}}-2\left( x\text{ }+\text{ }1 \right)\text{ }+\text{ }2\left( y\text{ }+\text{ }1 \right)\text{ }=\text{ }0 $

$ {{x}^{2}}~+\text{ }1\text{ }+\text{ }2x-{{y}^{2}}-1-2y-2x-2\text{ }+\text{ }2y\text{ }+\text{ }2\text{ }=\text{ }0 $

Simplifying further we get,

x2 – y2 = 0

Therefore, the transformed equation is x2 – y2 = 0.