The point to which the origin is to be shifted to remove the first degree terms from the equation $2 x^2+4 x…

The point to which the origin is to be shifted to remove the first degree terms from the equation $2 x^2+4 x y-6 y^2+2 x+8 y+1=0$ is
  1. $\left(\frac{7}{8}, \frac{3}{8}\right)$
  2. $\left(\frac{-7}{8}, \frac{-3}{8}\right)$
  3. $\left(\frac{-7}{8}, \frac{3}{8}\right)$
  4. $\left(\frac{7}{8}, \frac{-3}{8}\right)$

Solution

$2 x^2+4 x y-6 y^2+2 x+8 y+1=0$ is in the form of $ \begin{aligned} & a x^2+2 h x y+b y^2+2 g x+2 f y+c=0, \text { we get } \\ & a=2, h=2, b=-6, g=1, f=4, c=1 \end{aligned} $ Required point $ \begin{aligned} & =\left(\frac{b g-f h}{h^2-a b}, \frac{a f-g h}{h^2-a b}\right)=\left(\frac{-6-8}{4+12}, \frac{8-2}{4+12}\right) \\ & =\left(\frac{-14}{16}, \frac{6}{16}\right)=\left(\frac{-7}{8}, \frac{3}{8}\right) \end{aligned} $

Asked in: AP EAMCET 2017 (26 Apr Shift 1)

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