Question

The axis of the parabola $x^2 + 2xy + y^2 - 5x + 5y - 5 = 0$ is

• A. $x + y = 0$
• B. $x + y - 1 = 0$
• C. $x - y + 1 = 0$
• D. $x-y=\frac{1}{\sqrt{2}}$

Answer 1

Answer: (A)

$x + y = 0$

Answer 2

Given, equation
$x^{2}+2 x y+y^{2}-5 x+5 y-5=0$
$\Rightarrow (x+y)^{2}=5 x-5 y+5$
$\Rightarrow (x+y)^{2}=5(x-y+1)$
$\therefore$ Axis of the parabola is $x+y=0$