Question

decide which of the following are quadrstic equation
x+1/x=-2 ?​

Answer 1

Answer:

x+1 if x=-2 then x+1=-1

the answer is -1

Hope my answer helps

Answer 2

Solution:-

We have

$\rm \to \: x + \dfrac{1}{x} = - 2$

Simplify the equation

$\rm \to \: \dfrac{ {x}^{2} + 1}{x} = - 2$

$\rm \to \: {x}^{2} + 1 = - 2x$

Method:- 1

$\rm \to \: {x}^{2} + 2x + 1 = 0$

$\rm \to \: {x}^{2} + x + x + 1 = 0$

$\rm \to \: x(x + 1) + 1(x + 1) = 0$

$\rm \to \: (x + 1)(x + 1) = 0$

$\rm \to \: x = - 1 \: \: and \: x = - 1$

Method:- 2 By quadratic formula

$\rm \to \: {x}^{2} + 2x + 1 = 0$

Quadratic formula

$\rm \to \: x = \dfrac{ - b \pm \sqrt{ {b}^{2} - 4ac} }{2a}$

We have a = 1 , b = 2 and c = 1

$\rm \to \: x = \dfrac{ - 2 \pm \sqrt{ {2}^{2} - 4 \times 1 \times 1 } }{2}$

$\rm \to \: x \: = \dfrac{ - 2 \pm \sqrt{0} }{2}$

$\rm \to \: x = - 1 \: \: and \: \: x = - 1$