possible answer...

method I. (very tedious)
apply equation as given.
substitute different values of x and calculate corresponding values of y.
mark out the points and join the points together to form your curve.

method 2. (much easier & more efficient)
recognise that the given equation is an equation of circle in general form.
convert to standard form to make it easier to see the coordinates of the center, and radius of the circle.
sketch the circle.

Thanks

Vignesh, for an equation of that form, if the coefficients of x^2 and y^2 are the same, the shape will be a circle. If they are not the same, it will not be a circle (A Level stuff). Sometimes, it will be an oval (in A Level, called an ellipse). Sometimes, it's other weird looking graphs.

Oh ok. No wonder, the x^2 and y^2 are same coefficients of 4. I watch this point in future. Thanks!

To see this, simply divide both sides of the equation by this coefficient (in this case, 4). You will get x^2 + y^2 + ... which is your circle equation.

Yes. I do that.Thanks.