Find the centre and radius of the circle given by the equation $$2{x^2} + 2{y^2} + 3x + 4y + {9 \over 8} = 0$$.

What will be the equation of the circle whose centre is (1, 2) and which passes through the point (4, 6)?

The number of common tangents to the circles $$x^2+y^2=4$$ and $$x^2+y^2-6x-8y-24=0$$ is,

If $$3x+y+k=0$$ is a tangent to the circle $$x^2+y^2=10$$, the values of k are