If `2x^2+lambdax y^+2y^2+(lambda-4)x+6y-5=0,` is the equation of a circle, then its radius is :

Explanation

`2x^2+lambdaxy+2y^2+(lambda-4)x+6y-5=0`

`x^2+lambda/2xy+y^2+(lambda-4)/2x+3y-5/2=0`

`lambda/2=0,lambda=0`

`x^2+0+y^2-2x+3y-5/2=0`

`C(1,-3/2)`

`r=sqrt(1+5/4+5/2)`

`r=sqrt((4+9+10)/4)`

`r=sqrt23/2`.