In order to eliminate the first degree terms from the equation $2 x^2+4 x y+5 y^2-4 x-22 y+7=0$, the point…

In order to eliminate the first degree terms from the equation $2 x^2+4 x y+5 y^2-4 x-22 y+7=0$, the point to which origin is to be shifted, is
  1. $(1,-3)$
  2. $(2,3)$
  3. $(-2,3)$
  4. $(1,3)$

Solution

Given equation is $2 x^2+4 x y+5 y^2-4 x-22 y+7=0$ Here, $a=2, b=5, c=7, h=2, g=-2, f=-11$ To eliminate 1st degree terms origin is to be shifted to the point $\left(\frac{h f-b g}{a b-h^2}, \frac{g h-a f}{a b-h^2}\right)$ $\begin{aligned} & =\left(\frac{-22+10}{10-4}, \frac{-4+22}{10-4}\right) \\ & =\left(\frac{-12}{6}, \frac{18}{6}\right)=(-2,3)\end{aligned}$

Asked in: AP EAMCET 2007

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